gave him the poison and how big the doses she gave of the poison right up until the last day. it's amazing on june 21st, 1978, 22-year-old karla brown was found brutally murdered in the basement of her home. it looked as if the killer had committed the perfect crime, and police could find very little evidence. but years later, investigators noticed something on a crime scene photograph that had previously been overlooked. the killer had left behind a clue. 22-year-old karla brown and her fiance, a man we'll call

mark hart, had recently purchased a home together in wood river, illinois. although the couple had a rocky past, friends and family saw this as a beginning of a new phase in their relationship. >> karla brown was a beautiful young woman, was very popular in her hometown in the wood river area, was one of those girls that everybody knew. girls liked her. guys liked her. she was just one of those people that was special, and everybody recognized that. >> on june 21st, karla brown took the day off from work to unpack and spoke to one of her friends on the telephone. >> maybe we can have you over for dinner. >> they had talked for a few minutes. they had talked about getting >> together later on that afternoon. >> wait a second. i just heard something at the door. >> and karla interrupted the conversation and said, listen, i'll have to call you back. i'll see you later. there's somebody at the door. that was the last that her friend ever talked to her.

>> around 5:30 that afternoon, carla's fiance and his friends stopped by the house after work. when they walked into the basement, they saw a horrible sight. >> karla! karla! >> karla was lying face down in a bucket of water. >> she had her hands tied behind her. there was evidence of struggle, a death struggle in the basement. and a very strong suggestion of a sexual rape. >> but investigators were confused about some of the things they saw. there were two men's socks tied around carla's neck. they were tied neatly, inconsistent with what you would expect to see in a life and death struggle. the white electrical cord used to tie the victim's hands was not tight enough to effectively restrain an individual in an assault. >> there was too much length of cord behind her to where her hands behind her could come up in front of her.

she would have access to the attacker, given that much freedom with the length of rope that was tied between the two wrists. >> she was found wearing a sweater her fiance said she would never wear in the summer. the top button was fastened, another inconsistency with a life and death struggle. the socks around carla's neck were from inside the home. the mate to one was found in the dresser. the other was under the sofa in a puddle of water tinted with blood. the sofa cushions were also wet, and there were blood drops on the floor near the sofa. in the rafters was a coffee carafe from the kitchen. to homicide investigators, it looked as if the coffee carafe had been used to rinse blood from the sofa cushions. the attack occurred near the

sofa, and the body was later moved into an adjacent room and placed into a barrel of water. the crime scene staging told investigators that the perpetrator spent a great deal of time inside the house after the murder. but who knew that karla brown was home and alone on the day of the murder. and who would have felt free to spend so much time in the home cleaning up and staging the scene. police began their investigation with a close look at karla brown's fiance. you fifteen percent or more on huh, fiftcar insurance.uld save yeah, everybody knows that. well, did you know that playing cards with kenny rogers gets old pretty fast? ♪ you got to know when to hold'em. ♪ ♪ know when to fold 'em. ♪ know when to walk away. ♪ know when to run. ♪ you never count your money,

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the autopsy report on karla brown indicated death by strangulation. although she was found nude from the waist down, there were no signs of sexual assault. investigators were convinced that the killer spent a great deal of time in the house after the murder staging the crime scene. >> i didn't know mark very well. although they had dated for a number of years off and on, and

there were times in their relationship that it wasn't great. but she seemed to always be crazy about him anyway. >> police also questioned two neighbors who had been sitting in the yard next door on the day karla and her fiance were moving in. >> hey, karla brown. i'm john prante. we went to school together. remember me? >> hi, how are you? >> both men had alibis as to where they were on the day of the murder, and they both willingly took lie detecter tests and passed. with no other leads, police asked the fbi for a psychological profile of the killer and turned to fbi behavioral analyst, john douglas. >> in my research, we began to break down crimes by disorganized and organized. disorganized means extremely

sloppy, carelessness on the part of the offender. the crime could be very, very impulsive. organized means there's a high degree of criminal sophistication on the part of the subject. >> to douglas, this crime scene was disorganized, an indication that the killer was inexperienced and had probably never killed before. he came to the home with no intention of committing murder but did so after some sort of confrontation or rejection. since he spent so much time inside the home, douglas believed that he was familiar with the victim and her routine and might be living in the neighborhood or very close by. douglas said the killer was an unmarried white male in his mid to late 20s, high school educated, with a sloppy appearance. the use of electrical cord to tie the victim's hands indicated

that the killer had taken shop classes or had vocational training. douglas also told investigators that they may have already interviewed the murderer and that he was capable of passing a polygraph test. >> then it got kind of spooky. i was sitting there, and i wasn't sure i was believing what he was saying after a certain point. he started talking about how this individual would react and what kind of vehicle he'd be driving, and he started talking about a volkswagen. there's a high probability this guy would be driving a volkswagen, and it would be red or orange in color. >> this led investigators to focus once again on the two men sitting next door on the day karla brown and her fiance were moving in, but investigators needed more than just a psychological profile. they needed hard evidence.

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a crime scene technician remained deeply troubled by the karla brown murder. for one, he and his colleagues could not determine what caused the wounds on karla brown's face and chin.

the first real break occurred when he attended a seminar on image enhancement in new mexico. dr. campbell taught that seminar. dr. campbell was demonstrating a photographic technique that uses cameras, monitors and computers to show details of crime scene photographs that can otherwise not be seen. >> this was used by both engineers in nondestructive testing of materials and also by archaeologists looking at area photographs to find ancient ruins. >> after the seminar, bush told campbell about the karla brown case. >> i said, doc, do i have a case for you. and i told him about the karla brown case, and we were never

able to determine what type of instrument damaged her face. >> i asked him to please send me the photographs that they had of the deceased person and to also send me an autopsy report. >> dr. campbell used his image enhancement equipment to look more closely at the crime scene photos of karla brown. the system not only improves the contrast of the photographs, but can also create what appear to be three-dimensional views, adding depth to the image. when dr. campbell was through, he knew what caused the injuries to karla brown's face. >> he tells me that the tv tray may have been the instrument that she was hit in the head with. this tv tray was lying on the floor within three foot of the victim where she had probably been on the couch, but i had

missed it. >> the tray tables were still in storage, untouched in the two years since the murder. in an extraordinary piece of luck, dr. campbell found microscopic traces of blood and hair still present on the tray table. and what dr. campbell said next was even more revealing. >> he says, what about the bite mark? i said, bite mark? what bite mark? what are you talking about? >> when we looked at the photograph and went ahead and enhanced it and magnified it, present on the shoulder was a bite injury on the shoulder. and by looking at that bite injury, you could actually pick out individual teeth all the way across. >> i'd trade that for five eye answers any time. eyewitnesses can make mistakes that fingerprints don't.

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two years after the brutal murder of 22-year-old karla brown, investigators got the break they needed when a photographic enhancement revealed a bite mark on karla's shoulder. police now turned to the two men sitting in the yard next door when karla brown moved into her new home. both matched the fbi's behavioral profile of the killer. police checked their alibis again. although both had passed the polygraph tests, police discovered that john prante had spoken about the murder to others. >> john prante had mentioned to his friends that he had seen her body that day, that he looked over the shoulder of some policemen while they were investigating in the basement, and he described the condition of her body. he even mentioned she had bite marks on her neck and collarbone. >> the police were the only ones

inside the house after karla brown's body was found. >> it was a shock to us as police officers because there's no way that he could have known that unless he put the bite mark there. also the information about the location of the body, the way the body was found, the only way that would have been known is to either have been there on the investigation or put the body there yourself, because we never released that information to the public or to the media. >> since the bite marks were overlooked during the original autopsy, investigators wanted to make sure nothing else was missed, so karla brown's body was exhumed for a second autopsy. this time it was performed by dr. mary case, the chief medical examiner for st. louis county. >> the original autopsy, there was the ligature strangulation and the body was examined. and for some reason the head was not examined, so i opened the

cranial cavity and there was bruising in the scalp. somebody struck her on the head. the question is whether or not, for example, this blow would cause loss of consciousness. >> dr. case thought that karla brown may have been alive when she was placed in the barrel of water because when she was found, there was foam around her mouth. >> because she was in water and she was producing that foam, i feel like there may be some component of drowning, even though she had been strangled. she was still, maybe to a minimal degree, breathing because i believe she may have breathed in some water. >> during the autopsy, more photographs were taken of the suspected bite wounds, which were sent to the new york state police forensic unit for an independent evaluation. prosecutors wanted to make sure that the mark on karla brown's

neck was, in fact, a bite wound. >> in my opinion, the pattern injury on karla brown's neck had all the characteristics that a bite mark would have. >> the doctor was asked to compare the bite wound to three different dental casts. the doctor had no idea to whom the casts belonged. after making wax impressions of the models, the doctor concluded that two of the models were not consistent with the bite wound. >> i took the third model and examined all the individual characteristics that those teeth would have caused, compared those characteristics with the characteristics on the clarified photograph of karla brown's neck that i had, and came to the opinion that only that model was consistent with having caused

that pattern injury, or that bite mark. >> he measured the teeth. he went back to the photograph. he turned them different ways. he held them up in the air. finally, he laid the dental impressions on the table, and he pointed to them and said, that's your man. >> model number three belonged to john prante. interestingly, prante also matched john douglas' psychological profile. he was in his late 20s. he had a history of troubled relationships with women. he attended industrial art school and had an unkempt appearance. he spent a lot of time in the neighborhood, often visiting next door to carla brown. and just as john douglas had predicted, prante had passed an earlier polygraph test. the unusual aspect of douglas' profile was the prediction that

prante would be driving a red volkswagen. >> where that came from, only john could say, but it turned out that that individual did, in fact, have that volkswagen. >> prosecutors believe that when carla brown's fiance left for work, john knocked on the door. >> maybe we can have you over for dinner. >> karla was talking on the telephone. >> wait a second. i just heard somebody at the door. let me call you back. what do you want? >> need some help moving in? >> i want you to leave. >> can't we talk a little? >> i want you to leave now. >> there was some kind of argument or struggle, possibly after she had rejected prante's sexual advances. he forced her into the basement and hit her with a tray table. at some point, he bit her on the shoulder and strangled her.

afterwards, he staged the scene to make it appear to be a sexual assault. but when he changed her clothes, he made the mistake of fastening the top button, the first clue that the scene had been staged. he tied her hands with electrical cord, wrapped the socks around her neck, and placed her into the water while she was unconscious but still alive. prante tried to remove the bloodstains on the sofa with water he carried from the kitchen and the coffee carafe, which he left above the rafters and the sofa. the clothes karla was wearing that day were never found. prante may have taken them as a trophy.

in july of 1983, john prante was tried and convicted of first-degree murder and was sentenced to 75 years in the state penitentiary. >> he got caught because of the techniques of investigation of law enforcement overwhelmed him. he got away with the crime because he was lucky. he got caught because law enforcement changed his luck. >> don webber, along with journalist charles bosworth, chronicled the many ups and downs of this case in a best-selling book "silent witness." >> carla's family was so intrigued by the bite mark evidence that she embroidered a tappestry as a token of her appreciation. and it offers the slogan don used, you can lie through your teeth, but your teeth don't lie.

and around the border is the pattern of rectangle-space, rectangle-space-triangle. which is the bite mark pattern proved to be made by john prante. prante. on the morning of february 20th, 1989, something terrible happened to janice johnson, a 35-year-old housewife and mother of two children. >> claire, i've got to go. i'll talk to you later, okay? >> the investigation into that morning's events would raise questions that persist to this day. clayton and janice johnson lived in the tiny coastal fishing village of shelburne, va