The woman knew Sylvester Antonio Ray when she saw his photo. She identified him as the man who had raped her seven years before.

"There are just certain things you never in life forget," she said. "I'm not sure how they figured out who he was."

The woman's identification of Ray as the man who raped her in April 2003 allowed DeKalb County police to arrest him last year not only for her attack but also for three other cold cases. What police didn't tell her was that if detectives had followed a critical clue in 2002, she and two other women may never have been raped.

Ray, 40, is on trial today in DeKalb County Superior Court on charges of raping four women in 2002 and 2003 as well as other charges including armed robbery, kidnapping and aggravated assault. The trial could prove embarrassing for law enforcement. Not only did detectives fail to solve the case in 2002 despite having evidence linking Ray to the first rape, but much of the evidence, including two rape kits, has disappeared during the nine-year delay.

Prosecutor Ingrid Skidmore told the court at a bail hearing last year that her office believed Ray was a serial rapist who only quit raping after he was arrested on weapons charges and sent to federal prison.. After serving five years, he was released in 2008 and moved to Indiana, according to court transcripts.

Skidmore, who handled pre-trail hearings, left the DeKalb office two months ago and District Attorney Robert James will serve as lead prosecutor. Jury selection began Monday.

Ray is facing trial only because the Georgia Bureau of Investigation in 2010 finally ran DNA tests on backlogged cases that revealed one man was responsible for all four rapes. That information allowed DeKalb police Lt. Joseph Craig Popp to re-open the case.

At a pre-trial hearing, Skidmore said after Popp learned of the DNA link, he pulled all the incident reports. He found a first victim,, who had been attacked in July 2002, had memorized the tag number from her attacker's car after he dumped her in a secluded location. The Atlanta Journal-Constitution does not identify victims of sexual assault.

The then 21-year-old victim provided the plate number to police but it was apparently never thoroughly investigated.

"The police didn't really follow up on that tag number at the time," Skidmore told Judge Linda Hunter. "That tag number becomes important."

John Shane, a former police captain and now a professor at John Jay School of Criminology in New York, said the failure to follow up an obvious lead was a pure case of neglect, especially since the tag should have flagged the crime as solvable and made it an investigative priority.

Popp traced the plate to a car owned by a woman and when he ran a search on the woman's known associates, Ray's name popped up. Skidmore told the judge Ray had been living with the woman for a decade, according the transcript.

The detective found a photo of Ray among DeKalb mug shots. He put together a photo line-up and the second victim identified Ray as her rapist.

Popp next tracked down the other three victims and two positively identified Ray. When Popp contacted Ray's probation officer in Indiana, he learned Ray was back in DeKalb for a family reunion, according to court records.

He was arrested and swabbed. The DNA was a match, authorities said.

Valerie Knight, who described herself in a letter to Hunter as Ray's long-term fiance, said it is inconceivable that Ray would have raped anyone..

"Sylvester's personality and warmness appear to draw people toward him, especially women," she wrote."

Knight also wrote his personality did not fit the brutal rapes. She noted his past convictions -- larceny, having stolen property, illegal drugs -- were non-violent offenses.

"He has never been physical with me or the kids," she wrote. "Sylvester is not a violent or aggressive individual."

Popp testified at a pre-trial hearing that he had been unable to locate much of the physical evidence from detectives' earlier investigations. Missing evidence included crime scene photos, two rape kits, clothing and investigative notes and reports.

Trial experts say defense lawyers can seize on the lack of a common patterns to cast doubt on the claim that Ray is a serial rapist. That makes the DNA evidence more critical because the passage of time can be used to undermine the eyewitness identification, said local defense attorney Tom West.

He said the missing rape kits probably would not undermine the case as the GBI had preserved DNA samples to be tested. But the missing evidence made the police look sloppy. Shane, the law professor, called it rare for police to lose so much evidence and said it warranted an internal investigation.

Attempts for a response from DeKalb police or the DeKalb District Attorney were unsuccessful.

The woman who originally identified Ray from his mugshot did not indulge in any finger-pointing. She was only glad to finally have been able to identify her attacker.

"I'm just glad that he is in jail and the case is almost over," she said. "One sick person is off the streets."