DENVER (AP) -- Vincent Groves was released from prison on mandatory parole in 1987, having served five years for strangling a 17-year-old girl. Three years later, he was back, this time for two more murders, and would eventually die behind bars.
Investigators long believed Groves was responsible for at least three additional murders, and possibly more, while he was walking the streets of Denver and its suburbs after his 1987 release.
Now, 16 years after his death, they've been able to confirm their suspicions in at least one of those slayings. Authorities believe he killed at least two other women after his release, based in part on evidence that they were strangled.
If he were convicted of a similar strangling today, chances are Groves would have been behind bars when those killings happened.
"They're not letting anybody out" now, said David Wymore, a former state public defender who represented Groves in the late 1980s. "Nothing from Groves' case can transcend into today. It's a whole different world."
As authorities investigate more old murder cases, they are finding links to Groves. Through DNA, they believe he killed three people in 1979, Denver District Attorney Mitch Morrissey said. They believe he could be responsible for up to 20 slayings in all.
Many of those killings happened between 1979 and 1988. Groves was arrested for the killing of teenager Tammy Woodrum in 1981.
His wife at the time had convinced him to turn himself in. Groves then showed up at a suburban Denver police department with Woodrum's body in a camper. Groves told his wife at the time that he accidently shot her.
Groves said he and the teenager had left for a fishing trip in the mountains west of Denver when Woodrum overdosed on cocaine.
He said he panicked and tried to make the scene look like a robbery and at one point had taken Woodrum's body out, tied her hands and then tried to make it look like she had been raped. An autopsy determined she had been strangled, apparently with a ligature.
Prosecutors placed him on trial for first-degree murder, but a jury convicted him of second-degree murder and gave him a 12-year sentence.
At the time, the Colorado Gorsuch Bill of 1979 mandated parole for inmates, Groves included, after they served a fixed percentage of their sentence. Groves got out after serving five years.
Sentencing reform in Colorado that began in the mid-1980s ensures that inmates spend decades in prison, especially for crimes of violence.
The changes in Colorado followed President Ronald Reagan's signing of the Sentencing Reform Act of 1984, which established minimum sentences for federal offenders, and is widely seen in legal circles as a move away from a focus on inmate rehabilitation to sentences in proportion to the crime.
Today, a second-degree murder conviction in Colorado carries a minimum sentence of 16 years, with a maximum of 48 years. A prisoner doesn't become parole eligible until they've served at least 75 percent of their time, Wymore said.
Unlike the 1980s when release happened automatically, today an inmate goes before a parole board.
First-degree murder carries a mandatory life sentence, with death the maximum penalty.
As an example of how the system worked in the early 1980s, before Groves went to prison for Woodrum's slaying, he was released from custody while his case was appealed, Morrissey said.
Groves stopped to pick up a prostitute in an area of metro Denver historically known for prostitution, but the undercover police officer on a sting operation recognized him and wouldn't get in the car with him, Morrissey said.
He was sent to prison on Aug. 4, 1982. He made parole and was released on Feb. 13, 1987.
Authorities launched a task force in the late 1980s, while Groves was out of prison, 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, Groves was suspected of up to 20 killings between 1979 and 1988, he said. In one case from 1980, investigators had recovered semen, 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.
More DNA testing is pending to determine if Groves is linked to other victims, Morrissey said.
Jim Burkhalter, a retired Denver police detective who was part of a team investigating the deaths of Denver prostitutes in the late 1970s, said they were hampered by potential witnesses who may have been prostitutes but didn't trust police.
"They didn't want to be dragged into court," Burkhalter said. "They didn't want a snitch jacket tied to them because they needed to go back to the streets and begin working again."
Wymore said the cases in which Groves was suspected of would have been difficult to prove in court. "Problem was, most of these women had somewhat of a past," Wymore said. "They were not exclusive. What they needed then was fingerprints."
Prosecutors declined to release the names of victims' family members, and efforts by The Associated Press to reach them were unsuccessful.
Groves died in prison of natural causes in 1996 while serving a life sentence for the April 29, 1988, first-degree murder of Juanita "Becky" Lovato, 19, and a 20-year sentence for the July 25, 1988, second-degree slaying of Diane Montoya Mancera, 25.
Four of Groves' suspected slayings are now classified as solved after police used a DNA profile of Groves they recently found from the Woodrum case to match with DNA found at crime scenes.