High-Tech Heats Up Cold Crime Trails : Forensics: Special police units in several cities are combining new techniques and old-fashioned legwork to help solve cases.

They jailed one killer before he could deliver his speech to the PTA. They helped find a skeleton under a stairway. They tracked fugitives all the way across the seas.

The cops call them the cold-case squads.

Many of them are seasoned detectives from the old school who are fast becoming high-tech sleuths able to use computer-age developments and scientific advances to help solve aging homicide cases.

And, they say, time isn’t necessarily working against them.

“People need to understand now if you kill somebody and get away with it 15 years, you’ll still have to look over your shoulder, because we still may be coming to get you,” said Sgt. Jerry King, one of four detectives in the Dallas squad. “It’s not over.”

Police departments across the country are operating the special units, according to Sgt. David Rivers of the Metro-Dade Police Department in Miami. His squad, established in 1983, was one of the nation’s first. Other cities with similar programs include Boston, Jacksonsville, Fla., and Columbus, Ohio.

“Certainly we didn’t create this concept,” said Lt. Ron Waldrop, who organized the Dallas task force in March, “but I don’t see how a major city, with the new developments in technology today, can avoid having some similar type program.”

Sometimes old evidence such as blood, hair or fingerprints--given a fresh look using the latest forensic tools--can reheat a killer’s trail.

Other times police get a break from changed allegiances or a number tucked away in a file that has been dusted off for review.

King said the Dallas squad has solved some murders “by going back and just merely looking at a Social Security number, tracking the number and finding the people.”

The people in the case of John Ayers, whose throat was slashed in November, 1977, were two women in Tucson and Houston.

According to police, Ayers left a suburban Dallas bar to party with several men and women he’d befriended. During a stop, three men walked into a wooded area where one man attempted to rob Ayers. He resisted. His throat was cut from ear to ear.

Detectives, looking at the case 16 years later, found a Social Security number they subsequently fed into a computer. The database didn’t exist at the time of the initial investigation. The numbers led to Tucson, then to Houston.

King remembers the Texas woman’s words when she came face to face with police:

“I knew you were coming. I didn’t know when, but I knew you’d be here eventually.”

“And she told us all about it,” King said. “Helped us solve the case.”

One of the killers told police who arrested him in Abilene, Tex., that he had to hurry back home to Dallas, 170 miles away, because he was scheduled to speak to the PTA the following night about drug abuse.

“He never went home,” King said. “I think he had just put this all behind him, just thought it had gone away. Obviously that was not the case.” The man is serving a life sentence.

Old-fashioned legwork remains at the heart of a good detective’s game plan. But police are now aided by enhanced fingerprint identification systems, genetic testing and elaborate computer databases filled with tracking information such as birth dates, driver’s license numbers and vehicle registrations.

In eastern Texas recently, state authorities were asked to investigate the murders of five people abducted from a Kentucky Fried Chicken restaurant in 1983. They used DNA testing and a torn fingernail found on the body of one of the victims. The son of a former state legislator has been indicted.

But DNA testing is often not as useful as other technologies because physical evidence either wasn’t kept or wasn’t stored properly until the last decade, police say.

The Automated Fingerprint Identification System can provide an abundance of fresh leads in timeworn homicides. Police can retrieve a list of suspects or witnesses by feeding sometimes as little as a partial print into a statewide database of more than 3.5 million fingerprints already stored.

“We got a lot of hits on that AFIS system,” said Detective Linda Erwin, taking a break from poring over a 1970 case she’d been handed earlier in the day. “A lot of them heretofore were unidentified fingerprints. We didn’t know if they were significant to the murder investigation or not. . . . Some belong to people who had reason to be there, but until recently we didn’t know that.”

Police also are starting to tap into Drugfire, an FBI-developed system that computerizes cartridge shell casings.

Although cold-case squads are becoming more common, not every department can afford the expense, Rivers said. “I’ve sent people to Europe, South America, Central America,” he said. “We just had a guy we extradited back from Holland.”

Tips have also come from faraway places, Rivers said. Police in Nicaragua relayed a man’s confession about killing his daughter and burying her beneath the stairs in a house.