The man who shot and killed a Buffalo, N.Y., photographer and strangled his elderly neighbor in April 1982 left four witnesses alive in the studio on that afternoon. To keep them from identifying him in a lineup or mug book, he splashed an acid-based solution in their eyes.
The case remained unsolved for nearly 20 years until a nationwide effort to classify imprisoned felons by their genetic fingerprint provided identification the Buffalo witnesses couldn't.
Come spring, Ishmael Saladeen will stand trial in the killings because his genetic code - gleaned from a blood sample and stored in the New York prison system's DNA databank - matched the DNA in semen obtained from a female victim who was raped in the terror attack, according to the prosecutor.
Across America, the science of DNA is changing the conventions of the criminal justice system - and much more. It gained national prominence for exonerating prisoners of crimes they didn't commit. Now, and increasingly, the same DNA technology is helping crack unsolved crimes, identify serial offenders and convict the guilty.
In the Manhattan District Attorney's Office, veteran prosecutors are reviewing "cold cases" for evidence that can now be re-examined. In California, Wisconsin, Texas and New York, rape charges are being filed against "John Doe" defendants who are known only by their genetic code. Lawyers are challenging as obsolete the statute of limitations for rape - it can range from five to 10 years - because of DNA testing.
Police inspect a crime scene for evidence that would seem inconsequential before DNA testing - a cigarette butt, a postage stamp, a pair of glasses, items that might have biological traces of the suspect.
About 13 law schools have formed student-staffed "innocence projects" - there's one based at American University's Washington campus - to identify the wrongly convicted through DNA analysis of evidence.
In the Buffalo case, Saladeen had been a suspect from the start, but "we had nothing to get this guy without DNA," said Joseph M. Mordino, the original prosecutor assigned to the case who is still on the job. Even today, he said, "There is no identification. There are no fingerprints, no other evidence. Only the positive result from his blood and the sperm from the rape kit."
But Saladeen's lawyer, Joseph J. Terranova, questions whether a jury would convict on DNA evidence alone. "Are you willing to ... say that evidence is so impressive you're willing to convict on that evidence alone, 18 years after the fact," he said. His client maintains his innocence.
While databanks in New York and elsewhere have helped reopen old cases like the Buffalo one, the expansion of such repositories has detractors. Dr. Edward T. Blake, a forensic scientist and pioneer in the use of DNA analysis in criminal cases, said, "The public is being sold this bill of goods that DNA technology is a magic bullet for solving violent crimes - it is not."
Blake, who has testified in hundreds of court cases involving DNA analysis of biological evidence, said the technology is "very valuable. No question about it. But its value is exploited in a particular kind of case, that being sexual assault." In most crimes, there is no biological evidence left by a suspect, he said.
Databanks can't address "the biggest concern to most people in society, and that is the rape that is happening today in your city," said Blake, who would prefer to see the millions budgeted for DNA databases spent investigating crimes.
With states retaining tissue or blood samples from prisoners, concerns also have been raised about the use of the material for scientific research, for example, on a genetic trait for pedophilia.
Paul B. Ferrara, the director of Virginia's state crime lab and a member of National Commission on the Future of DNA Evidence, said states have restricted the use of databank information to forensic identification.
"The 13 genetic locations that are the gold standard for forensic identification purposes are specifically selected because those sections don't code for physical characteristics, medical conditions or traits. None of those," he said. "I wouldn't know how to analyze some gene that is a predisposition to breast cancer."
DNA is shorthand for deoxyribonucleic acid, a fundamental building block of life, and its discovery in 1953 won the Nobel Prize for two British scientists. It is composed of four organic substances whose arrangement in a cell is unique to an individual.
DNA can be culled from blood, semen, bone, saliva, even hair roots. DNA analysis enabled researchers to identify the remains of Czar Nicholas II and his wife, locate the presence of tuberculosis in the Americas before Columbus arrived and discover the gene related to prostate cancer.
Its first legal application was in 1987, when Florida convicted Tommie Lee Andrews of rape using the DNA technology to show that the semen left by the rapist belonged to Andrews.