in 1990, a killer of a 22-year-old girl left an almost indistinguishable mark in a blood stain at the crime scene. but a new computer forensic technology found distinguishing characteristics in the smear, evidence that would lead directly to the perpetrator. richmond, virginia, is a city steeped in history. as the former capital of the confederacy, richmond keeps close ties to its past and a watchful eye on the future. with six colleges and

universities, thousands of young people move here each fall to go to school. 22-year-old dawn bruce had attended virginia commonwealth university. >> dawn was a musician. she joined the vcu wind symphony after she was accepted through auditions. that's what kept her there for as long as she was there. but dawn was anxious to find out what was out in the real world and how she could do and what she could do. >> after college, dawn worked as a phone operator by day and a waitress by night. despite the long hours, she enjoyed the freedom of living on her own. >> dawn was a fun-loving kind of person, thought she could do anything and everything, and didn't care what other people said about her trying to do things that weren't the norm.

>> on december 19th, 1990, dawn's mother went to her daughter's apartment since she hadn't heard from her in a few days. she found dawn in a pool of blood. the medical examiner found evidence she had been raped, sodomized, and stabbed in the heart. >> a knife was rammed in her heart, and the subject held dawn down until she bled to death, which, from what i understand, could have been eight to ten minutes or longer, and she was defiled in the process of this. i don't know how much vileness is needed, but that's only my opinion. i think it was a very, very bad case. >> first impression i had was what a horrible, horrible crime and what somebody had done to really an innocent young lady, who absolutely didn't deserve what happened to her in any sense of the word.

>> investigators discovered that the killer entered the apartment through a window, which had been pried open, but there was no evidence of burglary. nothing had been disturbed or broken. they found no foreign fingerprints inside the apartment. >> when i left there, i didn't have very good feelings at all because i think everything that i carried out there at the scene was in one large bag, and that consisted mostly of the items on the bed, the bed sheets and pillows and the blankets and so forth. >> investigators tom tillar and jim dorton interviewed dawn's neighbors in the apartment complex. several neighbors were suspicious right from the start. >> a subject who lived directly beside the victim was on active parole, and he was on parole for burglary and attempted rape while armed with a knife, so

immediately we felt that he was a good suspect. >> but with no murder weapon, no witnesses, and few leads, it was going to be a difficult investigation. ♪

food should be good. strawberries should sing. lettuce should be dirty. dressing, clean. debates should be healthy. hatchets buried. tables should be full. and good food should be good for you. we're not saying these are the rules we should all live by. but it's a good place to start. panera. food as it should be. plaque psoriasis. moderate to severe isn't it time to let the real you shine through? introducing otezla, apremilast. otezla is not an injection, or a cream. it's a pill that treats plaque psoriasis differently. some people who took otezla saw 75% clearer skin after 4 months. and otezla's prescribing information has no requirement for routine lab monitoring. don't take otezla if you are allergic

to any of its ingredients. otezla may increase the risk of depression. tell your doctor if you have a history of depression or suicidal thoughts, or if these feelings develop. some people taking otezla reported weight loss. your doctor should monitor your weight and may stop treatment. side effects may include diarrhea, nausea, upper respiratory tract infection, and headache. tell your doctor about all the medicines you take, and if you're pregnant or planning to be. ask your doctor about otezla today. otezla. show more of you.

shortly after the rape and murder of 22-year-old dawn bruce, john alderman was assigned to prosecute the case. >> when you get a crime like this that really violates a person, you get a sense of indignation that's impossible to escape. a sense of indignation at someone being used and abused like that. >> investigators began focusing their attention on the few bits of physical evidence they had. forensic experts discovered that the fatal injury was a single stab wound in the heart. in the forensics lab, scientists found two linear impressions on the pillowcase that were consistent with the blade of a knife.

the serrated edges appeared to be those of a hunting knife. also on the pillowcase, they found what appeared to be a partial fingerprint in dawn's blood. but the fabric was textured, which made any kind of fingerprint analysis impossible. >> the print was almost invisible. even to a trained eye, the ridge detail was very faint. and we had to really study it because as we studied it under magnification, you enlarged the fabric weave which had a tendency to totally eradicate the ridge detail. so at that point in time, i did not have a whole lot of hope for that fingerprint. >> there was ridge detail on the print, but in my opinion at the time, i didn't think it was very much. i knew if that's all we would ever have and it could not be enhanced in any way, then we wouldn't have much of a case

unless we got a lot more evidence coming in that we didn't think we would get. >> traces of semen also were found at the scene. serology tests indicated that the killer had type "a" blood. this eliminated dawn's boyfriend as well as dawn's neighbor, who was on parole for rape and burglary. dawn had another neighbor, robert knight, who had some prior arrests for drug possession. >> robert knight made comments to the victim as she was outside washing her car or going to and from her automobile to her apartment. this subject would make comments to her in a sexual suggestive nature, and he became a suspect. >> robert knight had type "a" blood consistent with the semen sample from the crime scene, but he had an alibi for the night of the murder. he said he was with his

girlfriend at the time, and the fingerprint on the pillowcase did not appear to match the fingerprints on file for robert knight. >> we tried traditional photography, everything that we knew at that point in time also, to develop some contrast between the ridges and the fabric. but basically, those techniques were not satisfactory at that point in time. we couldn't get it to a point where we felt like we had an identifiable print. >> scientists tried various chemical processes to improve the print on the pillowcase. but every time they enhanced it, they also enhanced the threads of the pillowcase. investigators were no closer to identifying the print on the pillowcase than they were the day after the murder. >> the fingerprint was something that we knew we had. it clearly was observed. it clearly was seen. but no one knew what to do with it because it was in a medium,

in blood on a medium on a pillow case against a pattern of the pillow case that made it unreadable. and if there was some way to make that print readable, it could take on as vibrant a forensic persuader as dna evidence and maybe some more. >> then investigators got a break. >> every year we have a latent print conference which encompasses all the latent print examiners in virginia. it's a training seminar, basically. the imaging people there, one of the vendors brought their imaging system there. >> i was highly skeptical of it. had never seen it used in a forensic case. but since we had nothing else other than this very faint print on fabric, we thought it was worth a try. >> the new system was called image enhancement technology. image enhancement uses a computer to identify patterns

like those woven into the pillowcase. once the pattern was identified, it was subtracted from the image, leaving only the ridge patterns of the fingerprint behind. after ten hours of testing, the fabric pattern was subtracted, and what began to emerge was a partial thumbprint of the killer. we're going to start watching a movie in the chevy malibu. ♪ (kids laughing) he's flying ok guys, pause the movie we're going to watch the rest in the toyota camry. hit play again ehhh. what happened? you can't watch the movie. ugh... no network connection. who wants to go back in the chevy malibu? me! let's go! peace out! chevrolet. the first and only car company to bring built-in 4g lte wi-fi to cars, trucks and crossovers. this is cool. yeah.

visit tripadvisor orlandondo tripadvisor not only has millions of real travelers reviews and opinions but checks hundreds of websites so people can get the best hotel prices to plan, compare and book the perfect trip visit tripadvisor.com today

investigators knew that they had to identify the fingerprint on the pillowcase in order to solve dawn bruce's murder. the primary suspect in this case was one of dawn's neighbors, robert knight, who had a history of drug abuse. knight said he had an alibi, that he was with his girlfriend on the night of the murder. but his girlfriend said knight wasn't with her for the entire evening. >> the evidence indicated the crime occurred about between 3:00 and 4:00 roughly that saturday morning. he claimed to be with his girlfriend all night, but his girlfriend said, no, he was not with me for about that period of time between 3:00 and 4:00. >> the fingerprints on file for robert knight did not have enough ridge detail to determine

if they matched the print on the pillowcase. knight voluntarily gave a second set of prints, but again it was not enough ridge detail to make a comparison. >> each time we would show our presence around him, he got a little bit more standoffish and not as cooperative and accused us of harassing him. he just changed entirely his personality and his willingness to help. he did not want us to come around anymore. >> now the prosecution was in a difficult position. if they could not identify the fingerprint as knight's, the defense attorney would use that against the prosecution at a trial. >> defense attorneys would have said, whose fingerprint is it? we don't know. we'll never know. and that fingerprint is the killer and it's not his fingerprint, or can't be proved to be his fingerprint. so in our line of work you really need to answer all the

questions. and if you don't, the defense attorney asks those questions at closing argument. >> but prosecutors gambled. they arrested knight for dawn's murder, pinning their hopes on the new fingerprint technology and the scientists' ability to match knight's fingerprints. after knight's arrest, norm tiller kept a close eye on the technique police used to fingerprint him, making certain that each finger was carefully rolled from nail to nail for the clearest set of prints possible. >> as soon as i saw a good suitable rolled print, i took that straight back to my office and began that examination. >> but tiller did not rush to judgment. he took his time. after one month of analysis and retesting, norm tiller found what he was looking for.

the print on the pillowcase was a left thumbprint. it matched the outside of robert knight's left thumb. >> i spent additional time doing comparison work and just analyzing the print from every angle, so to speak, before we actually effected the identification. and even then, i had another examiner go behind me and take a look at everything that i had done to make sure there were no errors made in the process. >> but there was one more hurdle. the image enhancement technology was so new it had never been accepted as evidence in court. >> i was concerned at that point in time that the evidence may not be accepted within the scientific community as good science. >> a hearing was held to determine whether forensic evidence from this new fingerprinting technology should be admitted.

the defense argued that it was hocus-pocus technology, which manipulated and changed the image of the fingerprint. pam ringer was the expert who testified for the prosecution, explaining that the human eye can distinguish between 16 and 32 shades of gray. but a computer can distinguish 256 shades. ringer said the image enhancement technology simply eliminated the fabric patterns, then made the dark areas of the fingerprint darker and the light areas between the ridges lighter. >> if somebody as dumb as i am can understand this after i got done with her through the course of the day and do some studying afterwards, i think the explanation becomes one that anyone can understand. >> this imaging enhancing doesn't change the data at all. what we had was a photograph of the fingerprint.

and pam ringer said, i went ahead and did it that day, on march 27th, i could do it again today. i can replicate it 100 times if i need to. >> she did it in stages. she first took the pattern out. then she took the weave out. and as you watch it, you can see the print didn't change. the print didn't move. the lines of the lands and grooves of the print didn't change at all. i think, graphically, that was the best persuader for the judge in the case. >> the judge was convinced. he did not believe that the computer enhancements altered the bloody fingerprint. a legal precedent had been set, but prosecutors wanted more than the fingerprint before heading to trial. you probably know xerox as the company that's all about printing. but did you know we also support hospitals using electronic health records

for more than 30 million patients? or that our software helps over 20 million smartphone users remotely configure e-mail every month? or how about processing nearly $5 billion in electronic toll payments a year? in fact, today's xerox is working in surprising ways to help companies simplify the way work gets done and life gets lived. with xerox, you're ready for real business. every auto insurance policy has a number. and life gets lived. but not every insurance company understands the life behind it. ♪ those who have served our nation have earned the very best service in return. ♪ usaa. we know what it means to serve. get an auto insurance quote and see why 92% of our members plan to stay for life. meet thsuperpower.ewest energy surprised? in fact, america is now the world's number one

natural gas producer... and we could soon become number one in oil. because hydraulic fracturing technology is safely recovering lots more oil and natural gas. supporting millions of new jobs. billions in tax revenue... and a new century of american energy security. the new energy superpower? it's red, white and blue. log on to learn more.

s robert douglas knight was charged with the capital murder of 22-year-old dawn bruce, but police still didn't have the murder weapon. a faint fingerprint left on a flimsy pillowcase would be considered firm evidence in court, and prosecutors soon had a lead on the murder weapon.

six months after the murder, a maintenance man working in knight's old apartment discovered something behind an access panel in knight's old bedroom. >> i don't know what possessed him to do that. i think there was a plumbing problem that caused him to take it off. when he did, he looked in and found a hunting knife and a sheathe. >> in the forensics lab, scientists performed a simple test to determine if this was the weapon used in the murder. using photographic overlays, the pattern of the knife was compared to the knife impressions found on dawn bruce's pillowcase. they matched. the final piece of evidence was the dna testing of the semen found at the crime scene. it matched the dna profile of robert knight.

prosecutors believe that dawn bruce arrived home from work around 1:00 a.m. and went right to bed. sometime around 4:00, robert knight went to the front window of dawn's apartment, pried it open, and crept upstairs. he stabbed dawn in the heart, then sexually assaulted her as she bled to death. but knight made mistakes. he wiped the knife on the pillowcase, leaving the impression of the murder weapon later matched to the knife found in knight's apartment. he also left a partial bloody fingerprint on the pillowcase, matched with the latest in computer technology.

facing an overwhelming amount of physical evidence and in an effort to avoid the death penalty, robert douglas knight pled guilty. he was sentenced to four life terms in prison. >> i'm very disappointed that robert knight didn't get the death penalty. i think he deserved the death penalty. i think the forensic science played a major part in solving the case. some cases are solved just by pure interviewing without any evidence and they are solved, but i think this is one of those cases that would not have been solved had it not been for the forensic evidence that was there at the scene. >> when we arrested knight, we had a bare circumstantial case. that's all we had, and it went to being the absolutely strongest forensic case that i've ever prosecuted in 40 years. >> the only thing that stands out with me personally is i

believe robert knight deserved and should have received the death penalty. i don't believe he deserves to be breathing, eating, sleeping, laughing, whatever emotions he may experience. i know one of these days he'll probably be walking the street again, but it will be a long time. even though justice was served, i think he was deserving of the death penalty. >> i told my other daughter, one day when we were talking about life and about her plans for family, when she said that she didn't think she was going to have children because she didn't know that she could go through what i had gone through. and i told her if i knew ahead of time that dawn was going to be murdered, i would still have had dawn because she brought such joy to us as her family,

not to ever not have children for fear of loss, because life for fear of loss, because life is not a guarantee. -- captions by vitac -- www.vitac.com breathtaking beaches and beautiful bodies explain why southern california is often the first choice for motion picture and still photographers. in 1995, linda sobek, a busy model with a growing reputation, vanished on her way to a photo shoot. linda's photographic images helped launch her career and would also solve the mystery of her disappearance. herma