they were a gorgeous couple. >> from the minute you saw her, you felt happy being with her. >> he was a proathlete, football royalty. she was expecting their first child. >> the baby was moving. she said come feel my tummy. >> then, the beaming mother to be gunned down in her own home. >> bullet holes. my sister was murdered. terrible. >> so full of love and life. who would want her dead. >> they are naming me as the

suspect? >> or one of his other girlfriends. >> letters were spilling secrets. did someone want her out of the way? a mother to be killed and a mother of three who is not what she seemed. now, an under cover plan to catch a killer. deadly liaison. thanks for joining us. i'm lester hold. it's a story of celebrity and mystery. it centers around chicago's hometown heroes. they were expecting their first child. no one was expecting it to end in the deadly way that it did. here is rob.

>> reporter: it was morning in a coo complex in the upscale chicago suburb of deerfield. the day was getting started. quiet. until the scream. a woman in the building heard it. she called her neighbor upstairs. >> are you okay. i heard a woman screaming pretty loud. would you give me a call, please. >> reporter: no response. now feeling something like dread, the neighbor picked up the phone again and dialed 911. >> i heard a woman screaming. it's been totally silent. >> reporter: the police rushed to the scene. the woman was right to call 911. the pregnant neighbor was dead. what happened upstairs and why? solving the mystery would lead to a beloved football player,

several women in his life and set the stage for a cat and mouse stage and who they think killed an expected mother in cold blood. her name was ronnie ryder. >> from the minute you saw her, you felt happy just being with her. >> reporter: ronnie was stunning, stylish and sweet. her brothers adored her as did their wives, anna and laurie. >> ronnie is the person you see that you would want to be. she was everything. she would do anything for anybody. >> she was very caring. always thought of other people. she called us every night.

that's just the way she was. >> reporter: after ronnie left their hometown, she stayed close to her family, including her nieces and nephews. >> she was always there. she loved being with family. >> there was one tenderness she brought everywhere she went. >> reporter: she was a woman with no enemies. who on earth could have wanted her dead? the investigation began at a crime scene that was only minutes-week-old. the detectives from the deerfield police department caught the case. >> you could still smell the odor of gun powder. >> no signs of struggle. >> reporter: bullet cases from a a .9 millimeters gun. >> there was emotion or something driving the shooter. in all likelihood, they could have known. >> who is the first person you

want to talk to? >> the boyfriend. >> reporter: her boyfriend was an exfootball player. they met in 1990 at a charity event. back then, sean was a member of the iconic '85 bears team that won the super bowl. >> for the most part, they were together all the time. they talked every day on the phone. they took trips together. >> reporter: ronnie's family said they seemed to make it work. the pro-athlete and girl from a small town. she juggled two jobs, one in the food industry and the other part time at macy's because she loved fashion. in march 2007 after many years with sean, ronnie became pregnant at age 41. she would finally become a mom.

it was obvious when wade, his wife and parents visited her in september. >> it's the happiest i have seen my sister in her life. >> the baby was moving. she said mom, come feel my tummy, the baby is moving. i'll never forget that. >> reporter: ronnie was a woman in love. this was no conventional relationship. they were together for close to two decades. they never married. anna wondered why she stayed with him. >> i said what is it about him? she said i don't know, i just love him. >> reporter: it was unclear in things would change. did she want to get married? >> yes. >> reporter: did he? >> i don't know. >> reporter: the family rarely saw sean. ronnie said he was a private person. just as they were wondering how

a baby would affect their relationship, she was gunned down that october morning. >> that was probably the most angry i had been in my life. i was in an uproar. immaterialed to grab the person myself and do what they did to my sister. >> reporter: police were committed to bringing the killer or killers to justice. they started the investigation by the book. look at the people closest to the victim. that's why they wanted to talk to sean gayle. they didn't have to wait long to do it. >> sh is sean gayle they are naming me as a suspect? >> suspect or grieving naming me as a suspect? >> sulook, every day we're using more and more energy. the world needs more energy. where's it going to come from? ♪ that's why right here, in australia, chevron is building one of the biggest natural gas projects in the world.

enough power for a city the size of singapore for 50 years. what's it going to do to the planet? natural gas is the cleanest conventional fuel there is. we've got to be smart about this. it's a smart way to go. ♪

rhoni reuter, more than six months pregnant was shot to death in her own home. it was especially shocking in deerfield, a tranquil, affluent chicago suburb which had not seen a murder in more than 30 years. who could have committed such a crime. first on the list of people police wanted to talk to was shaun gayle. she didn't know rhoni was dead and sounded confused about what happened. >> i been getting calls from the media, this is shaun gayle and they are naming me as a suspect.

is rhoni reuter okay? >> no, she's not. >> i'm driving to her house now. >> don't go to her house. come to the deerfield police department. don't go to her house, okay. shaun? come to the police department. do you know where it is? hey, shaun, do you want me to stay on the phone until you get here? >> police. >> reporter: shaun seemed shocked. police weren't buying it. you are listening to see if he's acting or if it's grief? >> it appeared to be sincere. >> reporter: you are not basing any conclusion on that tape? >> no. >> reporter: you want to talk to him? >> exactly. >> reporter: he may be football royalty, but now he was a

potential suspect in a high profile murder case. detectives say shaun was still emotional as they sat down and talked to him. where had shaun been at the time of the shooting? >> he was early and decided to get a haircut in north chicago. >> reporter: he's not far from the murder scene at the time of the murder? >> no, he's not. >> reporter: the barbershop confirmed he had been there the morning of the murder. >> we pulled a video of the complex which captures the alley to drive out and through. he is captured leaving the house. >> reporter: does that video tape clear him of being at the scene at the time? >> yes. >> reporter: no gunshot residue was seen on shaun. he does not match the description of a young male with black hair wearing a baggy sweat

suit. it didn't let shaun off the hook. they had to consider whether someone else connected to shaun committed the crime. the victim's family was thinking the same thing. >> at first i thought it was someone hired as a hitman doing this and that was them running if the scene. i didn't think the person would be stupid enough to do it themselves. >> reporter: did you think it could be shaun gayle? he didn't want the baby in the picture? >> he didn't know what to do. >> reporter: reeling with questions and anguish, they went to her apartment to collect her things. >> we caulked in. it was stark quiet and cold and empty. it just, i felt awful. all of her stuff, but not her. it was awful. >> she had all the baby clothes people had gotten her on a great

big table next to the kitchen. >> bullet holes in the floor where my sister was murdered. it was terrible. >> reporter: as the family grieved, they hoped the police would find answers. one lead came when investigators asked se eed shaun gayle, if no whom? he gave a woman's [ bell ringing ]

♪ [ bleats ] ♪ ♪ [ male announcer ] bring the fresh flavors of the world right to your table. ♪ discover sabra dips. adventure awaits.

shaun gayle was a handsome and popular ex-football player for the chicago bears. now his girlfriend, rhoni reuter was dead. rhoni wasn't the only woman in shaun's life. they learned that from shaun himself. >> it was an open relationship. >> reporter: it was not exclusive? >> correct. >> reporter: one of the women he dated the year before might be responsible for rhoni's death. monika kurowska.

she was 27 at the time. he was 43. >> he was a person who i can truly open up in a gentleman manner. she said shaun never mentioned other women. she assumed she was the only one he was dating. late one evening, monika happened to be in shaun's neighborhood and stopped by his home. >> i stopped by the window, where i saw him sitting with another woman. i have never suspected there was somebody else. that was not for me. there was shock. >> reporter: she started knocking on his window. >> i got upset because they ran upstairs. if it was a friend, why not open the door? >> reporter: she admits breaking the window. she didn't intend to.

>> i was angry. i don't think i was ever cheated by anybody. it was shocking for me. >> reporter: she remembers confronting the other woman. i said are you seeing him? she said you don't know that he's seeing other girls? i said no. >> reporter: that night marked the end of their relationship. after that, women in shaun's life started receiving letters. >> he was not only seeing this one woman, but seeing many women at the same time, trying to suede these other ladies from seeing him. >> reporter: the letters contain angry allegations that he cheated and lied but copies of what looked like very personal e-mails between shaun and the women. and travel itineraries that he took trips with two other women.

one was written in poor english. shaun says the letters were full of lies and accuse monika of sending them. he got an order of protection against monika. the letters continued for more than a year. it seemed to shaun that monika was violating that order of protection. by the fall of 2007 shaun was so frustrated, he wanted monika jailed or fined. it was filed in court october 4, 2007. the same day rhoni reuter was killed. >> reporter: rhoni didn't have enemies but gayle did? >> yes. >> reporter: not only did they think the letters hads a direct connection to the murder but one was found in rhoni's purse the

day she was killed. how big of a break does that seem? >> if she mailed the letter and rhoni had the letter, she knew her letter. >> reporter: does she sound jealous? >> yes. >> reporter: motive? >> yes. >> reporter: she was training one of her regular clients who happened to live in a town next to deerfield. her alibi seemed to check out. as soon as you talk to the client, is she crossed off the list? >> not immediately. we don't know their relationship, if he could be lying or not. >> reporter: another woman popped up on the radar from tipsters. >> three phone calls from people who gave this name. the information they were leaving is she would be an individual capable of doing

something like this because of the relationship she had with shaun gayle. >> capable of this murder? >> yes. >> reporter: the plot, as they say, was thickened. coming up, who is this? >> she says she's always bragged about shaun gayle being her boyfrien reporter: police zero in in a single mother and they enlist shaun gayle to help them.

it feels like a short cut, even through customs.

it feels like everything's gonna to be just fine. it feels like the experience of a lifetime. that's what it feels like to be a member.

>> reporter: not long after rhoni reuter was gunned down in her own home in deerfield, illinois, her long time boyfriend, shaun gayle and a former lover were being investigated as prospects in rhoni's murder. now the mystery deepened. callers gave another name, another woman in shaun's life. she was a divorced mother of three, a chicago native who worked multiple jobs including as a real estate agent. she was also an aspiring fitness model. >> promoting sales of fitness equipment like we see all the

time. they met in 2006. marni's children were there, twins a girl and boy and a younger son, age 10. how was she with her kids? >> i saw a very controlled mom. protective and communicated well. she was liked by her children's friends. >> reporter: he took more than 1,000 photos of marni in 2006 and 2007. at nearly 40 years old, she was in great shape. marni was incredibly driven. >> she was looking for success in real estate and as a fitness model. >> reporter: was the modelling about an ego or money? >> his girlfriend did her make up. >> she had a lot of interests.

>> reporter: she was fascinated by police work, applied twice to be a police officer but was turned down. still, she was active in the chicago police department's neighborhood watch program. >> she wanted to make sure her neighborhood was safe and concerned about her children's safety. >> reporter: police continued to look into her background and learned about her connection to shaun gayle. jason heard what was going on between the two of them when she brought it up in a shoot. >> she mentioned shaun gayle and being involved in real estate transactions with him. shaun was involved with other people. it wasn't exclusive. she showed up at the shoots with a man as a family friend. she was seeing a few men. it appeared to investigators and the photographer it was shaun she was really interested in.

on her last shoot, marni arrived with an outfit and request. >> she said i wore this specifically and i would like to get pictures specifically for shaun. it said chicago bears on the front and on her butt. she wanted to take pictures in this outfit for shaun. >> reporter: police were investigating those tips for callers pointing them to marni yang. one was from a former friend and what she told police refocused their investigation. >> she bragged about gayle being her boyfriend. she hacked into shaun gayle's e-mail account and obtained their information. monika was the one getting in trouble for it and she laughed that she might get deported.

>> reporter: she laughed about that? >> yes. >> reporter: what did that tell you about marni yang? >> she was indicative and would do anything to get anybody out of the way. >> reporter: hours after speaking with marni's former friend, police went to the alley and seized her garbage, no search warrant needed. they scooped up all her trash. in it, they found a bank statement. on that, they found she had been paying for background checks on other women gayle was seeing. she planned a trip to the same resort in mexico at the same time she was going there as rhoni. >> she said she was there to go scuba diving. >> reporter: she never said she wanted more from the relationship than what they had. basically, real estate dealings and sex. yes, sex. police thought it was interesting that marni would go to his house and have sex the

evening before the murder. when it came to women, shaun's life became complex. as police became interested in marni yang, they were crossing another off their list of suspects. they determined monika kurowska had nothing to do with sending the letters. the ordeal was a nightmare for her. >> it was mysterious. it sounded crazy. here in the middle, it's me, my name. i did nothing besides going out and dating the wrong person at the wrong time. >> reporter: shaun gayle was cleared of the murder within a few weeks of the shooting. the investigation was focused on marni yang and shaun went from possible suspect to unofficial police agent. he allowed police to wire his home, then he invited marni over to see what she might say about

the murder. investigators later said marni sounded like a concerned friend, not a killer as she asked questions about the investigation. >> did you talk to the police today? what do they think? >> reporter: police searched her computer. >> she googled rhoni reuters from work to her residence. >> reporter: police felt it was time to bring marni in for questioning. >> she talks about how she met shaun gayle and how they talked about real estate. >> reporter: investigators were interested in her where abouts at the time of the murder. that included a couple hours at his home. she was honest about that. >> she was there october 3rd at his residence. marni told them something else that night. something that would become central to the investigation. >> she tells us on that evening,

she was supposed to meet her friend for a real estate deal but had to cancel because her vehicle broke down. she had to stop at home to check on her kids. >> reporter: how important is that name? >> the most important piece to the puzzle. >> reporter: early january, 2008, police stepped up their investigation of marni yang and brought her, her children and her friend christy passion in for questioning. what they learned was surprising. especially from marni's older son. coming up -- police drop a bombshell on marni yang. >> all those things led your 16 yorld son to believe that you [ cow mooing ] ♪ [ female announcer ] there's no need to produce foods yourself to be sure they're 100% natural. ♪

now there's open nature foods from safeway. no preservatives, no artificial anything. all within budget. a wide choice of natural foods that meet your high standards. ♪ open nature. only at safeway.

open nature. e powerful. when not used in the right way, they can divide a nation. but when used wisely, they can bring us together in ways that make us stronger. words can connect us all... the more you know. >> reporter: three months after rhoni reuter was gunned down in her own home with a .9 mm baa rhett ta, police were zoning in on marni yang. marni was obsessed with shaun, loved guns and hated people who

got in her way. >> manipulative. >> marni stashed her firearms. they were hoping to find the murder weapon, a .9 mm ber rhett ta. >> they found evidence of marni's true feelings of shaun. they came across a letter she wrote to shaun, but never sent. in it, she complained you go on romantic trips everywhere, with all these other women and bring back to $2 key chain and i'm supposed to feel special about that? they found mailing labels to those women sent to women in gayle's life. police question marni on and off for three days. she was very talkative. she had answers for everything.

seemed confident, even cocky. marni's attitude was interesting to investigators. more important to them were the specifics of the case. they asked her about the murder weapon. marni told police she had had a .9 mm gun that went missing along with other things in her home. she did not report it. >> i did not make a police report because i had no homeowners insurance at the time. >> reporter: they asked her about a receipt from a book she ordered about how to make a homemade silencer. she said she bought them for a child's school project. >> there was no such project. when she bought the books, school hadn't started.

>> you have to start thinking about the project ahead of time. >> reporter: she changed the story and said she bought the books for a friend as a gag birthday gift. >> i got him tickets to the show and then that as a joke. >> reporter: police asked marni about the information she collected about women in shaun's life. she did that because shaun was getting closer to her children. she was a individual lent mother. >> i'm sorry but i make it my business that anybody in contact with my children, i will check you out. when i'm done, i'll check out your mother and sisters, too. >> reporter: police asked marni where she was at the time of the murder. she said she was home because she was having car trouble and her cell phone bounced of towers near her home that morning. there were witnesses she wanted to talk to.

marni's own children. >> the older son said mom was home. he stayed home from school sick. >> then they spoke with his sister who said marni asked her to lie for her. >> that's when he said, yes, i'm done lying for her. marni told him to tell police she was home with him the morning of the murder when she had not been. he startled police by what he said next. >> he told the investigators after hearing and seeing the story on tv, some of his friends brought it to their attention that one of his gut reactions is she somehow might be involved. >> reporter: his own mother might be involved in the murder of rhoni reuter? >> yes. very unusual response. it's a very honest response. the son would have no other reason to answer that way. >> reporter: police confronted her with what her own children said. >> all those things.

your 16-year-old son believes you are responsible for this. >> oh, god! i think this time is off a little bit but oh, like no way. >> reporter: investigators questioned marni's best friend, christy passion. they knew each other for 15 years since christie, a psychic read her cards at a fair. >> she denied having knowledge of marni committing the murder. >> believe it? >> no. >> reporter: they were convinced she was lying. they didn't have anything close to evidence. she had a gun like the murder weapon. she bought the silencer books and purchased parts to make them. purchased a bucket of cement the day after. they believe she lied about most of it on tape. they said it was not enough to

make an arrest. >> we don't have physical evidence tieing her to the scene. blood, hair, anything like that? >> no, no physical evidence. one of the questions i asked is can we put her near deerfield the morning of the murder? they said no. i said that's a problem. >> reporter: police checked security tape for the infiniti suv and found nothing. >> have you checked all potential avenues, rental cars, disposable cell phones. it is what they did. >> reporter: that turned out to be fruitful. >> she rented a car october 3rd and returned it october 4th. the rental was from enterprise. it led to the home of christy passion. more interesting was the odometer reading. >> it was a black volkswagen rabbit returned with 40 miles on

it. >> reporter: the detective had a hunch. drove from enterprise to christy's house to the murder scene. it was 40 miles. >> i know the route. i know she did it. >> reporter: this time he looked for a black vw. he watched the video more than 50 times and located what looked like the vw passing by less than an hour before the murder and speeding through just after the murder. there was a rental phone new. marni bought a disposable phone before the murder. she made a few calls on it. that was enough. >> there was one call that placed her in deerfield on the day of the murder. >> reporter: more strong evidence, but not enough. >> it was aggravating.

they pushed one more thing, one more thing. >> reporter: they worried the suspect would not be brought to justice. they thought they could convince someone to get marni yang to confess on tape. police were about to get her own best friend to turn against her. coming up -- [ male announcer ] when you come to new york from a place like detroit, no one expects you to influence the world of fashion. but when you grew up surrounded by rock 'n' roll and heavy industry, you just might make a name for yourself. ♪ that's what a blue-collar attitude can do in a white-collar world. ♪ now lease the all-new 2011 chrysler 300 for $339 a month for well-qualified lessees.

>> reporter: 17 months had gone by since rhoni reuter's murder and there's no arrests, not everyone a publicly named suspect. to the community, it seemed the case went cold. the police were working hard since day one, including months

preparing for a wiretap operation. they wanted to catch marni yang talking about the murder on the phone. as they geared up for that, police brought in christy passion a second time for questioning. >> if marni told anybody, this was going to be the individual. she knew more than she was letting on. >> reporter: police figured from a car rental form with christy's address on it she went there and stayed there the night before the murder. christy's employer records all phone calls. they found one placed at 9:11 the morning of the murder. it was a code. >> want to go to dinner? >> okay. >> that's fine. is everything all right? >> yeah. christy is bothered by something with that call. she's hesitating.

first thing at 9:00 in the morning you want to go to dinner? christy wasn't giving the police much. she relented. no deals were made, but once it was clear they had a lot of evidence, she opened up. >> we knew she knew, but not as much as she knew. it was a big wow. it was surprising. >> reporter: marni had nicknames for the girlfriends. rhoni's was miss macy's. marni asked her to bring out the taro cards and posed an unusual question. will i be successful in killing miss macy's. christy pulled out the sun card. >> it indicates success in whatever she was planning on doing. >> reporter: did christy try to talk her out of it? >> she did.

she believed she was going to go through with it. because of the past couple times she talked about it with christy and killing rhoni and she didn't follow through with it. >> reporter: before she went to sleep that night, if she was successful in killing rhoni reuter, she would call with a code. >> the code was going to be, do you want to go to dinner? >> reporter: then pure gold. the evening after the murder she goes to her home and confesses. >> she and her friend got in marni's car and stopped at dumpsters. she threw out a dark wig and was about to toss out a sweat suit. she said don't dispose of it, donate it. >> reporter: donate it? it's what they did. she showed them which dumpsters they visited that night.

she buried something. >> reporter: marni buried something small the night of the murder. christy had no idea what it was or how important or damming it would be. investigators needed a metal detector to find it. it was big for them and special to rhoni. >> it said pregnant. that belonged to rhoni. >> case closed? >> it was the piece of evidence they were looking for for 16, 17 months. >> reporter: it tied marni yang directly to the crime scene. the case was not closed. prosecutors wanted more. they wanted to get marni talking about the murder on tape. because she was so guarded on the phone, christy agreed to wear a wire and meet marni at the usual dining spot. christy, like shaun was an unofficial agent. she had ideas on how to trap her

best friend. >> she knew how her mind worked. >> reporter: what was the approach? >> we had information to link both of them to the scene. >> reporter: marni thought she was confiding but she was giving police an astounding confession. she told how she put it in a bucket of cement and threw it in the dumpster and explained what she wore the morning of the murder. >> a wig. dark sunglasses covering my face. i had dark make up on my face and i had gloves on. >> reporter: just like the mysterious person the neighbors saw. then she whispered details only the murderer would know. >> she started screaming. i took, i took the first shot. i remember screaming cause at

that point i realized we are now at the point of no return. any thoughts about turning back? i just emptied it. >> she described how rhoni started walking backwards in the kitchen, fell against a counter and fell on to the kitchen floor. >> she took a good kick at me in the shin. it was weak. i took one last shot in the head, finished her off. >> reporter: the next morning, after 17 months of pain staking investigation, police headed to marni's home and put one of her garbage cans in front of her garage door to block her in. the detective who logged more hours on the case than anyone else wrapped handcuffs around

her wrists. >> she asked what it was about even though she knew. >> reporter: she pleaded not guilty and went on trial of multiple counts for killing rhoni reuter and her unborn child. the state called the shooting an execution, cold, calculated, premeditated. there were a parade of witnesses including christy who testified against her once best friend and the pathologist who said rhoni died trying to shield her unborn child from the fatal shots. the defense attorneys argued she was a victim of the investigation that unfairly targeted her and never found physical evidence tieing her to the crime. in the end, her own words were hard to ignore. she was guilty on all accounts. she's filing an appeal of the

verdict and is sentence. shaun gayle declined to speak to "dateline." after the verdict, he talked about how difficult life has been since rhoni's murder and his regret about ever knowing marni yang and where that relationship led. >> the fact that rhoni's not here and we don't have a 3-year-old daughter. that's gonna be something that i live with. >> reporter: for the investigators who worked tirelessly on the case witnessing the conviction of marni yang was satisfying. >> did you see signs of remorse? >> no. at the beginning of the trial, she seemed confident, i believe she thought she could beat this. after christy testified and the audio, the look wasn't there anymore. she looked scared. >> reporter: how did you feel about that? >> good. she knew it was over. >> reporter: rhoni's family feels a weight has been