to let you down ♪ most of the evidence found that the crime scene hairs, fibers and fingerprints had been washed away, but the victim's six-year-old son unwittingly told investigators all they needed to know about the killer, and he did it without saying a word. the clue was in his genes.

a troop of boy scouts one sad morning in january 1988, their mission was to pick up aluminum cans for a recycling project. in the icy creek in rural ohio, they spotted what appeared to be a mannequin. >> they saw something just under the ice submerged. >> it was the body of a young woman. local police took every possible precaution to preserve trace evidence by wrapping the victim's body in a sheet before taking it to the morgue. a check of missing person's reports identified the woman as 32-year-old margie coffee, the single mother of two young children. she had been reported missing ten days earlier. >> the police found her vehicle down off of park avenue east by a bar and she was a missing person by the time this body was

located. >> the autopsy revealed that margie coffee had been strangled with her own scarf. the coroner estimated she had been dumped in the creek ten days earlier, the same day she disappeared. margie raymay was her maiden name. she grew up on the outskirts of a town named butler. >> she was an out going girl, personal. boy, she was a robust girl and she loved life. >> margie grew up in a loving religious home, but in her teenage years, as most kids do, she earned for independence, began spending most of her time in mansfield, a larger city about 15 miles northwest of butler. she made friends with an unsavory crowd. >> she got into some activities that were subject to prosecution by the law, and they were mainly

street crimes, that type of thing that probably were very low level but that's how we got to be acquainted with her. >> those street crimes allegedly included prostitution and illegal drug use. eventual t eventually, margie rejected that life and met a man named steve coffee. they married and had a daughter, angie but the marriage soured and margie and steve divorced. to support herself and her daughter, margie worked as a waitre waitress. she also enrolled in college to study law enforcement. and during this time, margie had another child out of wedlock, this time a son brandon. police investigating her murder wondered if margie had returned to the streets to support her children. as a police knew from experience, life on the streets meant special dangers and a large pool of potential

suspects. with no suspects or leads, police hoped that the rushing water of possum run creek had not washed away evidence, which could lead them to margie's killer. would you be willing to give up sharing your moments? sacrifice streaming all night long? is it okay to drop a connection, when you need it most? if you're not on the largest, most reliable network, what are you giving up? verizon.

does your mouth often feel dry? multiple medications, a dry mouth can be a side effect of many medications. but it can also lead to tooth decay and bad breath. that's why there's biotene, available as an oral rinse, toothpaste, spray or gel. biotene can provide soothing relief and it helps keep your mouth healthy too. remember, while your medication is doing you good, a dry mouth isn't. biotene, for people who suffer from a dry mouth. ♪ expected wait time: 55 minutes. your call is important to us.

thank you for your patience. waiter! vo: in the nation, we know how it feels when you aren't treated like a priority. we do things differently. we'll take care of it. vo: we put members first... join the nation. thank you. ♪ nationwide is on your side

when 32-year-old margie coffey was found strangled in a frozen creek, police wondered if her past had finally caught up with her. >> in her particular case, since she had a background of some activity that was certainly against the law, we looked into -- into that possibility, that she may have slipped back into that drug environment. >> but friends said that wasn't the case. margie had been focusing her attention on her family and her education. she had also rediscovered religion. >> i believe she wanted to be a christian lady. from all that i could gather from her, that's what she was striving for, to be better, to live better, to act better, and

forget all about anything in the past. >> police learned that margie had been actively dating since her divorce. among the men she was seeing were two mansfield police officers. one was robert lemon, a veteran of the force. >> he indicated to us that it ended sometime before that, a year and a half minimum, and that he had not had any contact with her or even spoken with her. >> the other was charles oswalt. he, too, said the relationship with margie was over. >> he was very much in love with his wife. oftentimes spoke about what they did on weekends and things like that. he was a type of police officer that other police officers i would say would try to emulate. >> lieutenant oswalt furnished a police report indicating he had been on duty that night on a drug investigation. >> we had no fingerprints.

we had no weapon. we had to explore the other possibilities, and those possibilities were really going to come from her. >> margie coffey was last seen alive at this diner, sitting in a booth with her school books open, studying for a class. detective david messmore interviewed the owner of the diner who said that lieutenant oswalt was in the diner the same time as margie. the two weren't sitting together, but they did acknowledge one another. >> fine. how are you? >> it was a very distressing situation. not only did i work with him, i knew he was a very good policeman. but i had been friends with him, and it was just -- it was very upsetting to me to think he might be involved in a crime

like that. >> when confronted with this information, lieutenant oswalt refused to comment. margie's parents laid their daughter to rest, an excruciating task few parents are prepared for. >> there were times that they would just break down and cry when they would see a picture or when mrs. remy would talk to me. >> little did police realize that margie's own son would provide a tantalizing clue, one that would lead them to the killer. f damage in your home. are you sure you're not ignoring them in your body? even if you're treating your crohn's disease or ulcerative colitis, an occasional flare may be a sign of damaging inflammation. and if you ignore the signs, the more debilitating your symptoms could become.

learn more about the role damaging inflammation may be playing in your symptoms with the expert advice tool at crohnsandcolitis.com. and then speak with your gastroenterologist. with the expert advice tool at crohnsandcolitis.com. [engine revving] [engine revving] [engine revving] ♪ introducing the first-ever 306 horsepower lexus rc coupe with available all-wheel drive. once driven, there's no going back. lease the 2015 rc 350 for $449 a month for 36 months. see your lexus dealer.

for over 19 million people. [ alex ] transamerica helped provide a lifetime of retirement income. so i can focus on what matters most. [ female announcer ] everyone has a moment when tomorrow becomes real. transamerica.

femalget 36 months er ] interest-free financing, when tomorrow becomes real. and save up to $300 on beautyrest and posturepedic. even get three years interest-free financing on tempur-pedic. plus, free delivery, set up and removal of your old set. and sleep train's 100-day money back guarantee. keep more presidents in your wallet. this special financing offer ends presidents' day at sleep train. ...guaranteed! ♪ sleep train ♪ your ticket to a better night's sleep ♪

as the search for margie coffey's killer continued, a mansfield police officer told homicide investigators about a suspicious incident that occurred the night margie was killed. the officer said he saw lieutenant charles oswalt, who had been linked romantically to margie, on foot, out of uniform, and behaving strangely near the police station. >> and he had a leather jacket on, which would be unusual at that time of the night due to the fact he was working.

>> what's going on? how are you doing? and he kind of ignored him. he continued walking to the police station through the back way. >> oswalt's behavior cast doubt on his claim that he was investigating a drug operation that night. >> for him to be nervous and excited in that period of time was kind of unusual. that kind of took the luster or the punch out of his alibi. >> in the forensics lab, margie coffey's clothing would soon tell a story of its own. >> i had the scarf. you had leg warmers. you had a heavy coat. once the clothing is dry, basically it'll be hung on a hanger just like your clothing would be at home. there'll be a piece of paper placed underneath in case anything naturally falls off. >> while most of the trace evidence had been washed away by

the water, a very small amount remained. >> recovered a number of hairs and fibers. in particular, two fibers red in color. the presence of these two fibers, about a quarter of an inch in length and no more twice the size of a human hair across, were all that we had to work with. >> while different fibers might look similar to the naked eye, under a microscope they are very distinctive. the foreign fibers on margie's coat and leg warmers were triangular in shape or trilobal. trilobal carpet is usually found in high-traffic areas like hotels and automobile interiors since it hides dirt. tony tambasco took carpet samples from every location margie had been in the days before her murder.

tambasco thought he found what he was looking for in the home of margie's parents. >> at margie's parents' house, we found a floor mat that actually had red carpet. the red carpet fibers in the floor mat looked very similar to those we had recovered from the victim. >> but under that microscope, those carpet fibers were not similar to the ones recovered. tambasco wanted to examine the police cruiser oswalt had been driving that night. most police vehicles are not carpeted because of heavy use and have rubber flooring instead. but police records revealed that on the night in question, lieutenant oswalt was the watch commander, and the watch commander's vehicle was

different from the others. >> unique about that particular cruiser, cruiser number 306, was it was a supervisor's car. it wasn't your standard police car that you buy every year with the fleet. it was bought at a public auction. >> the mansfield police had gone to an auction, had purchased a chevy caprice classic, a full-size car for their commanders. and of course the upper echelon had a little bit nicer vehicle than the guys in the street. >> the carpet in the watch commander's car was red. tambasco took a small sample from the vehicle. at first, it looked similar to the carpet in margie's parents house. but under a microscope, the fibers told a different story and were similar in all respects to the fibers found on margie's clothing. >> we looked at color. you can see the color is the same. we looked at diameter. you can see the diameter is consistent.

we looked at the trilobal design, and the pattern does show that. >> chemical tests revealed that both sets of fibers had been dyed with the same chemicals. but dye evidence is not definitive. >> the presence of the fibers being consistent with the fibers in the vehicle is not identification to the exclusion of all others. it is not absolute. there's no way anyone can come to court and testify that fiber came from that carpet. it's just not going to happen. >> but even more damning evidence for officer oswalt would come from margie's 6-year-old son, brandon. ♪

go! go! go! he's challenging the very fabric of society. in a post cannonball world! was it grilled cheese? guilty! the aquatic delinquency is a larger issue to this ♪ you did it again, didn't you? yup. ♪ anyone have occasional constipation, diarrhea, gas, bloating?

yes! one phillips' colon health probiotic cap each day helps defend against these occasional digestive issues... with 3 types of good bacteria. live the regular life. phillips' you can't breathe through your nose, suddenly, you're a mouth breather. a mouth breather! well, put on a breathe right strip and shut your mouth. cold medicines open your nose over time, but add a breathe right strip and pow, it opens your nose up to 38% more. so you can breathe and do the one thing you want to do,

sleep. add breathe right to your cold medicine shut your mouth and sleep right. breathe right. and look for the calming scent of new breathe right lavender, in the sleep aisle. [bassist] two late nights in blew an amp.but good nights. sure,music's why we do this,but it's still our business. we spend days booking gigs, then we've gotta put in the miles to get there. but it's not without its perks. like seeing our album sales go through the roof enough to finally start paying meg's little brother- i mean,our new tour manager-with real,actual money. we run on quickbooks.that's how we own it.

the circumstantial evidence in margie coffey's murder all pointed to lieutenant charles oswalt. so did the forensic evidence. the two red carpet fibers on margie's clothing were microscopically similar to the carpet in oswalt's automobile. but the question haunting police was motive. if oswalt murdered margie coffey, why did he do it? after margie had given birth to her second child, brandon, she told social services she couldn't identify the baby's

father since the pregnancy was the result of a rape. but later when she applied for financial aid at college, she was required to identify brandon's father and explain why she wasn't receiving child support. >> when she became a jehovah's witness and they began to counsel with her, they found these details out. they said, look, you can't lie. you're to tell the truth, and she named chuck oswalt as the father. >> with this news, prosecutors asked oswalt to undergo a paternity test. it revealed that the likelihood of oswalt being brandon's father was greater than 99%. investigators also discovered that oswalt had refused to pay for child support when margie

asked, possibly because he didn't want his wife to find out about his infidelity. >> lieutenant oswalt was married, had children. in fact, up until all of this, his wife didn't know anything about margie coffey, did not know he had a child by another woman. so i'm sure that her finding that out certainly was motive for what happened. >> oswalt allegedly offered margie a few thousand dollars from an insurance settlement, which margie refused as insufficient. during charles oswalt's murder trial, prosecutors presented one more piece of evidence against him. a woman, who once worked for police as a decoy in prostitution investigations. she testified that she, too, had been having an affair with oswalt. sawyer claimed that oswalt had not only told her he murdered margie coffey, he also provided details of the crime.

sawyer said that after oswalt and margie saw one another in the diner, they went to oswalt's police car to talk. they discussed the child support matter and oswalt's offer of $3,000 to end the dispute with margie's refusal. the conversation grew heated, and margie threatened to disclose that oswalt was brandon's father. margie slapped him. oswalt responded by strangling her with her own scarf. the forensic evidence reveals that oswalt put margie's lifeless body in the backseat of his police car where her coat and leg warmers picked up the

tiny red triangular-shaped carpet fibers. later, prosecutors say oswalt drove to the bridge over possum run creek and dumped the body into the water in the mistaken belief that any incriminating evidence would be washed downstream. >> you know, when it's yellow and it waddles and it quacks, it's probably a duck, and that's the case we had here. >> at his trial, lieutenant oswalt took the stand in his own defense and denied killing margie coffey. he repeated his claim, that he had been working alone that night on a drug investigation and offered the typed police report to prove it. but prosecutors contended that the report was bogus, implying that oswalt himself had typed the phony report after the murder to give himself an alibi. the jury found lieutenant charles oswalt guilty of

voluntary manslaughter and abusing a corpse. he was sentenced to 10 to 25 years in prison. to this day, oswalt insists he did not kill margie coffey. >> he may deny it, and he may go to the grave denying it. i think he is guilty. now, if i'm wrong, god forgive me. >> for residents of mansfield, the ultimate betrayal is a policeman who commits murder. >> i mean it's bad enough to murder someone. but then when you're supposed to be a protecting people, and then using the office of authority to kill someone, then that's the

lowest murder that i can think of. >> he will never, ever, ever admit that crime. i don't care if they keep him in jail until he dies. he will go to his grave with that in his mind. he will never, ever. and i really believe that. >> prosecutors say that it was solid police work and some luck that helped seal the case. >> the presence of these red fibers in that carpet was simply a shot in the dark. a police car in our own backyard, a police car in our fleet. the uniqueness of that police car being bought at auction, the chance of that, one in a million. >> and without the forensic evidence, lieutenant oswalt might not have been brought to justice. >> i will say this was one of the key pieces of evidence, and it would have been more difficult for a jury to convict him, if not impossible.

in a small town in oregon in 1984, the first biological attack was launched against the united states. for over a decade, the details of this nearly catastrophic event were with held from the public. this is how forensic science unearthed the biological trail. this small town in oregon is called the dales and penched high above the columbia river 80 miles due east of portland. >> it seems like it's from back t