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DNA cases also rely on low-tech investigations

Without recent advances in DNA analysis, the murders of three St. Petersburg women would still be a mystery.

But technology alone isn't enough. City investigators had to sift through old files and examine dozens of pieces of evidence.

It took a combination of traditional, shoe-leather police work and cutting-edge DNA analysis for police to identify the suspects.

"Some cases might have 50 or 100 pieces of evidence in them," said Sgt. Mike Kovacsev, the head of the department's homicide unit. "Detectives have to essentially reconstruct these cases."

Tuesday, city police said Tony Ables, 51, was responsible for two unsolved murder cases in 1983 and 1987. They also linked a 1990 murder to a man named Edward Pate, now dead.

Evidence from unsolved homicides and other serious cases is stored in the Police Department's basement headquarters at 1300 First Avenue N. Detectives often examine the old cases during slow spells; dozens of homicides have accumulated over the years.

Sometimes, new leads occur to detectives simply by looking at old evidence with fresh eyes. But last year, several detectives and investigators sent a batch of DNA samples collected from various crimes to the Florida Department of Law Enforcement for analysis.

Three cases came back with "hits," suspects whose DNA matched the samples. That's how police say they were able to identify Ables and Pate.

Ables, 51, is serving a life sentence. He was convicted in two other murder cases. Pate had AIDS and died in 1992 at 43.

Kovacsev said Ables may be responsible for several other unsolved homicides. A detective will continue to go through old cases that are similar and submit them for DNA analysis, he said.

Maj. Michael Puetz credited the work done by then-Detectives Rusty Zitzelberg and Rick Shaw and civilian Brenda Stevenson.

But he also pointed to a type of DNA analysis called short tandem repeat, or STR, with helping to identify the suspects.

STR is, in many ways, the most powerful type of DNA analysis available, said Connie Mulligan, an associate director of the genetics institute at the University of Florida.

It works like this: Each person has a unique set of genetic markers repeated in his or her genetic code; STR analysis compares a DNA sample taken from crime scenes to the DNA samples in a massive database of suspects, many of whom are felons required to provide samples. Experts say the replicated genetic markers that the technique identifies allows them to identify suspects with greater precision.

"It's the most powerful, the most accepted technique," Mulligan said.

Times researchers Caryn Baird and John Martin contributed to this report. Abhi Raghunathan can be reached at or (727) 893-8472.