DENVER (AP) -- Authorities all along had the DNA evidence to link a convicted a triple-murderer to four additional murders, and they say he could have been responsible for as many as 20 slayings.
But the process of developing an identifying DNA " fingerprint" was still five years away when authorities say Vincent Groves killed a prostitute, a banker, and a store clerk in 1979.
By the time Groves had been let out of prison in 1987 and went on a suspected killing spree that left police discovering a body a month in and around Denver for about a year, authorities were still struggling with how to handle DNA. Colorado was the first state to require DNA but only from sex offenders in 1988 and the FBI's national database was a decade away from becoming fully operational.
On Wednesday, Denver District Attorney Mitch Morrissey announced that through federal grants for a cold case unit in the Denver Police Department and his office, four slayings had been solved though DNA matches.
Groves, who died in prison in 1996 at age 42, was tied by DNA to the 1979 killings of women found strangled and partially nude in an alley, an industrial park and a bathtub in Denver. Police used a DNA profile of Groves they recently found from an old murder investigation and linked it to the four separate crime scenes, authorities said.
"So often times, a serial offender can fly below the DNA radar screen, maybe leaving DNA, but because their criminal history occurred at a time when they weren't eligible to go into the database or there was no database, they stay at large continuing to commit their crimes," Morrissey said.
The 1979 slayings of Emma Jenefor, 25; a store clerk in a tony area of Denver; Joyce Ramey, 23, a suspected prostitute, and Peggy Cuff, 20, a banker, bore strong resemblances to Groves' past killings and the disappearance of a woman that Groves was suspected in, authorities said. Police also linked Groves to the 1988 strangulation death of Pamela Montgomery, 35, a suspected prostitute found dead in an alley.
Groves would target women he knew who were addicted to cocaine or prostitutes he picked up on Colfax Avenue, a street in Denver historically known for prostitution, said Morrissey and Mylous Yearling, cold-case investigator for Denver's police department.
Groves strangled most of his victims; many were found nude or partially clothed, left in the mountains west of Denver, alleys and fields outside the city, police said.
When he died, Groves was serving a life sentence for the 1980s strangling of two young women. He had been released on parole in 1987 after serving five years in prison for killing a third woman in suburban Denver.
Authorities launched a task force in the late 1980s to investigate a string of slayings after authorities began finding an average of a body a month, all possibly killed by the same person, Morrissey said. At that time, Grove was suspected of up to 20 killings between 1979 and 1988, he said. In one case from 1980, investigators had seminal fluid, but could only develop a blood type from the sample.
"It was frustrating in that we didn't have DNA like we do now," Morrissey said of their efforts.
More DNA testing is pending to determine if Groves is linked to other victims, Morrissey said.
"There's families out there that deserve answers and that's what this work's about," Morrissey said. "If they're (the suspects) still there, still alive, we want to hold them accountable. So when they're not still alive, we're able to give families answers, tell them what happened to their loved ones."
Groves' DNA profile was recovered from the case file related to 17-year-old Tammy Woodrum. Groves brought her body in a camper to a suburban Denver police department in 1981, according to a court document, after his wife convinced him to turn himself in.
He returned to prison in 1990 for the slayings of Juanita "Becky" Lovato, 19, and Diane Montoya Mancera, 25.
Police had circumstantial evidence linking Groves to three slayings in the late 1970s, including Ramey, and one missing woman, said Morrissey, who unsuccessfully placed Groves on trial in 1988 for attempted murder involving a woman who had escaped.
Yearling -- one of an eight-member cold case team in Denver -- described Groves as intelligent and able to coax women into compromising situations. The 6-foot-5, 240 pound former athlete grew up in a quiet suburb northwest of Denver in a yellow ranch house, the son of a music teacher and a military serviceman, Yearling said. He worked as a security guard and as a supervisor for an office building cleaning crew and traveled around the city, Yearling said. Groves went to church regularly, and his prison record lists his religion as Adventist.
"This caught his family by surprise," Yearling said. "His family doesn't believe that he committed these crimes."
Neighbors outside Groves' family home said the family moved out in 2010. A man who said he's related to Groves declined to comment. Other family members could not be reached.
Prosecutors declined to release the names of victims' family members, and efforts by The Associated Press to reach them were unsuccessful.
Morrissey said that three of Groves' victims managed to escape. After a hitchhiker broke free in 1982, police found two knives, an opened liquor bottle, a pair of women's underwear and a piece of electrical cord with a slip knot tied to one end of it in a search of his car, according to a court document.
When Groves was dying in prison, detectives asked him to share the fate of his victims, but he refused, Morrissey said. Prison officials declined to say how he died.
Morrissey said Groves died of natural causes.