Between 1975 and 1995, dozens of young women were snatched off Denver-area streets, killed and dumped along rural roads, a crime spree that includes 38 unsolved murders that cold-case detectives believe may have been victims of a serial killer — or killers.

The crimes unfolded in a chilling pattern: An average of nearly twice a year during that 21-year span, the nude body of a young woman was discovered along a rural road or field around Denver.

Many were teenagers. Many were involved in risky behavior — such as prostitution.

And although some of the murders from that period were eventually solved, a new effort is underway by detectives from around the metro area — some working together, some working alone — to find the answers in the killings. Those detectives have submitted evidence from various cases to the Colorado Bureau of Investigation for DNA testing, hoping new technology might identify suspects.

The work is driven by a simple belief: that as many as a half-dozen serial killers stalked Denver-area streets for more than two decades.

Today, the detectives who have taken on the old cases are motivated by the desire to find justice for women long dead — and by the fear that some of those killers are still out there, preying on others.

“Sexual assault, strangulation and a desire to shock police were elements that drove the killer,” said Marv Brandt, a cold-case investigator for the Arapahoe County Sheriff’s Office. “That person might be 60, still capable of finding more victims.”

Four detectives from three different agencies are working together on 17 cases they believe may be related. Other investigators are looking at different groups of unsolved killings.

They have a tough job in front of them. As cold-case detectives sift through evidence of unsolved killings, they are looking for patterns that might match a signature method of a serial predator. Looking for weapons of choice, staging of bodies or similarities in victims, the detectives try to tie killings to a murderer already in prison or to a previously unidentified perpetrator.

The numbers are staggering: The unsolved deaths of 38 women from that time fit some pattern. Detectives believe as many as 11 of those could be tied to two serial killers who have been caught and convicted — although they lack the evidence to say definitively.

The remaining 27 are a mystery. Their killers could be in prison for other crimes. Dead. Or, at worst, still roaming the streets somewhere.

It’s that thought that drives the detectives.

Blood vessels burst

Tall weeds drooped in two parallel lines, marking the path where 18-year-old Karolyn Walker’s bare heels dragged behind her limp body. Her remains had been discarded and “staged” not far from East Colfax Avenue in east Aurora. Blood vessels had burst when she was strangled, staining the whites of her eyes with tiny red dots.

It was the Fourth of July in 1987, about midway through Colorado’s deadliest harvest. The way Walker’s body was posed would lead investigators to conclude her death was related to other body-dump cases.

By then, the killings had been occurring for more than a decade, but no one had made the connection that they were tied together — a result of the realities of the time. The bodies were found sporadically over years in numerous jurisdictions in the Denver metro area, in places such as Aurora and Denver, as well as Adams, Arapahoe, Jefferson and Weld counties.

During that period and since then the Denver area almost always had more than 100 homicides a year.

As was common at the time, detectives with each sheriff’s office or police department investigated their own cases, and there often wasn’t much communication with counterparts in other jurisdictions, Brandt said.

Many of the victims had engaged in risky behaviors — such as hitchhiking, prostitution and drugs. Several were runaways. They were usually beaten and strangled, but in some cases they were little more than skeletons by the time they were found and an exact manner of death couldn’t be determined.

Serial killers don’t always follow an exact script every time they kill, and there were some differences in some of the cases identified as being similar.

For example, there were differences in how some of the women were killed, said Cheryl Moore, Jefferson County Sheriff’s Office cold-case investigator and another of those involved in the new probe. And it’s possible that some cases are not linked, that a pimp or a boyfriend was responsible.

One of the inherent realities of unsolved murders is that even detectives working on the same cases come up with different theories and opinions about what happened or who was responsible.

Denver police Lt. Matt Murray, for instance, said he disagrees with detectives who have linked the murders of two women in the city to other cases. He points to the strangulation murder of suspected call girl Lea Lobmeyer in July 1992, a killing Denver detectives don’t believe is linked to the serial murders. But, he added, Denver would be willing to help other jurisdictions in any way they could if asked. And Adams County authorities have similar misgivings about other killings.

What’s not in dispute is that during 1987 and 1988, a rash of eight murders, in which women’s bodies were dumped in rural areas, led investigators from several departments to conclude that they were all part of the same pattern.

Together, 18 law enforcement detectives and investigators formed the Denver Metro Homicide Task Force in August 1988 to hunt down the “body dump” serial killer.

At the time, the belief was that one man was responsible.

A rapacious killer

The task force soon identified a killer who had been raised by staunch Baptist parents. A conflicted Vincent Groves was on a pious mission to rid Denver of prostitutes, said Douglas County Undersheriff Tony Spurlock, who helped capture the serial killer.

Groves had been released from prison Feb. 13, 1987, after serving five years of a 12-year sentence for strangling 17-year-old Tammy Sue Woodrum.

Authorities would come to suspect that Groves — who died in prison in 1996 — was involved in anywhere from five to 13 other murders, many of whom were prostitutes picked up along the Colfax Avenue corridor in Denver and Aurora.

One of a few exceptions to Groves’ normal pattern of preying on prostitutes was Diann Mancera, a 25-year-old hitchhiker from Denver whose body was dumped under an Interstate 25 overpass in Douglas County. Groves showed a tinge of remorse after killing a woman who wasn’t a prostitute and redressed her, Spurlock believed. It was his undoing: Groves’ semen was on her pants.

A jury convicted Groves of killing Mancera and 1988 strangulation victim Juanita Lovato, a 19-year-old Denver prostitute who was dumped in Adams County. To this day, detectives believe he was responsible for other killings — in March, Denver authorities announced that their detectives, prosecutors and crime analysts, working together, tied Groves to three 1979 murders.

As the original task force was working through the murders, it landed on a startling conclusion: Groves could not be the only killer. They began finding patterns between 1982 and 1987, the years when Groves was in prison for killing Woodrum.

The bodies of four girls and women found under similar circumstances to Groves’ victims were discovered during that span of time, including 18-year-old Donna Wayne, who was murdered June 13, 1986, said Steve Conner, Aurora cold-case detective. After Groves’ arrest Sept. 1, 1988, in the killing of Mancera, eight more victims were dumped, just weeks after the task force was formed.

One after another, their nude bodies were discovered along outlying roads, including the southern boundaries of Weld County, where Denver prostitutes Valerie Meeks and Tammy Lynn Cheeks were found with plastic shopping bags over their heads. Cheeks’ body was found in a field in July 1991, while Meeks’ corpse was discovered in November 1992, said Bill Hood, cold-case investigator for the Weld County Sheriff’s Office.

And there was another troubling problem that made it impossible to neatly connect all the cases to one monster.

The killer’s signature

Some of the bodies found while Groves was free — both before and after his imprisonment — were posed in the same provocative way as Wayne had been, and Groves was in prison when she was killed.

At least three other girls and women, including Walker, were all found posed near Interstate 70 in Arapahoe County. Their killer had manipulated their bodies as if they were mannequins, spreading their legs wide apart.

It was the killer’s signature.

It seemed unlikely to investigators that any of these were Groves’ victims. He had dumped his out of cars like trash, their arms and legs bent in unnatural positions, Spurlock said. And even more conclusive, witnesses have identified a white suspect in two of these cases; Groves is African-American.

There were at least 20 victims who, for one reason or another, didn’t seem to match Groves’ pattern. There was still a prolific killer stalking Denver who hadn’t been caught, and the task force had more work to do.

The task force’s formation had been the subject of multiple news stories. But its inner workings, outlined in a memorandum that was drafted before it was disbanded in the 1990s, and the ongoing work of a new generation of detectives have not been revealed until now.

In 1995, seven years after Groves’ arrest, the task force created a six-page “problem identification” report that concluded a pattern existed in which victims shared 13 common characteristics.

“During the past 20 years, 20 women have been murdered and deposited in rural settings around the Denver metro area,” the report said.

It was apparent the victims had been killed in other locations and driven long distances on busy roads.

“The suspect is brazen enough to actually transport a deceased corpse far enough in a vehicle to be in a somewhat rural or isolated area,” the report said.

The task force concluded, after much analysis, that it was only logical that at least some of the murders were committed by a serial killer. The conclusion would prove accurate after another serial killer was arrested and later convicted in two of the murders.

Task force members met for years to come but made no additional arrests, and the group eventually disbanded after they exhausted all of their leads without linking anyone new to the crimes.

A decade passed. Then, in 2005, Moore, the Jefferson County detective, was working independently when she broke one of the cases. The sheriff’s office had formed a new cold-case unit and appointed her as the first cold-case investigator. For Moore, the fact that they were old cases only meant that families of victims had been suffering that much longer.

“We investigate these cases to bring closure to families and the victims,” she said.

Moore was driven. She began organizing files of unsolved murders, tracking down evidence and reports. She looked for cases with evidence that might be solved with updated DNA testing.

Similarities in cases

But, in the end, hard work — not new technology — made the difference.

It started with the case of a Jane Doe, whose body was found in March 1989 by sightseers on Lookout Mountain, Moore said.

The case was very similar to that of another 1989 murder, that of Lanell Williams, a Denver prostitute whose slaying had been investigated by the homicide task force. Williams’ strangled body was found nearly a mile west of Golden on U.S. 6 in October of the same year Jane Doe’s body was found.

In 2005, Moore took a fresh look at the two cases and eventually concluded the cases were related. But in order to solve both cases, she needed to first identify Jane Doe. She scoured the case files of the two women and found an investigative gap. Sixteen years earlier, detectives had taken fingerprints from the unidentified corpse but hadn’t been able to match them to any fingerprint samples in state and federal databases.

Moore had a lab technician run the fingerprints in different ways. The third time, a match was made to a Denver prostitute, 33-year-old Lisa Kay Kelly.

DNA evidence — a science that was in its infancy in the 1980s — identified a suspect in Williams’ case: Billy Edwin Reid, 52, who was convicted of murdering both women and sentenced to life in prison in 2008. A witness statement and a letter Reid wrote also linked him to the murder of a third woman, Queena Sanders, whose body was found in Denver on Feb. 14, 1988. Her case, like Kelly’s, hadn’t been identified by the task force.

Denver police have presented the Sanders case twice for prosecution, said Lynn Kimbrough, spokeswoman for the district attorney’s office. She said the evidence wasn’t sufficient to prove Reid murdered Sanders beyond a reasonable doubt.

Still, Moore suspects that Reid committed other murders.

Moore had been working alone. Then, after Brandt retired from the Aurora Police Department following 22 years as a detective during which he often investigated homicides, he began working part-time four years ago for the Arapahoe County Sheriff’s Office.

When he reviewed unsolved county cases, he immediately recognized that the circumstances of two homicides were nearly identical to two unsolved murders he had investigated with Aurora. He called Conner, a longtime colleague, and the two, along with Arapahoe County cold-case investigator Bruce Isaacson, began looking at the cases together.

Their work convinced them that the same killer who posed the bodies of four teens between 1979 and 1986 — Walker; Kimberly Grabin, 16; Stephanie Bauman, 15; and Donna Wayne, 18 — may have also killed seven others.

Additionally, Moore said she found similarities between those cases and as many as five in Jefferson County and one in Larimer County, some that had also been listed by the ’80s and ’90s task force and some that had not.

But she remains cautious about definitively tying the cases together, fearing that it could hurt future prosecution if evidence later proves some are not connected.

More links may soon come

Those 17 cases — identified by detectives and investigators in Arapahoe and Jefferson counties — are linked by similar circumstances.

Brandt said most of the victims were pretty, petite, in their teens or early 20s. Most were killed after hitchhiking or visiting bars.

What bedevils the work of investigators is that none of the cases have been linked to one another by DNA or fingerprints. But those ties may soon come.

In recent years, investigators from Aurora and Larimer, Weld, Jefferson and Arapahoe counties have all submitted evidence to the Colorado Bureau of Investigation for DNA testing, but because of backlogs for the agency, they have already waited more a year for results in some instances. In others, the evidence has been returned without new DNA hits.

Although Denver was involved in the task force initially, its heralded lab, which has helped solve scores of cold-case rapes and murders, has not processed evidence linked to the serial cases, even though the victims were mostly Denver residents.

Murray said Denver police and crime analysts would eagerly assist in the investigation in any way they could, but they have not been called upon.

It’s a jurisdictional issue. Although the victims may have come from Denver, they were dumped in other counties.

“Just because they come from Denver doesn’t mean they were killed in Denver,” Murray said. “We have to say something happened here before we can say it has a Denver nexus.”

Detectives investigating the still-unsolved serial murders outside Denver don’t fault the department for not getting more involved in their cases. It’s accepted police practice: The jurisdiction where the body is discovered leads the case.

But in at least one of the serial cases, there was evidence the crime began in Denver: Brandt believes Walker was kidnapped in the city.

It could be the key to solving it and as many as 16 others.

Kirk Mitchell: 303-954-1206, kmitchell@denverpost.com, Facebook.com/kmitchellDP or Twitter.com/kmitchellDP

Suspects in cold cases

Raised by staunch Baptist parents, Vincent Groves was on a mission to rid Denver of prostitutes, according to Adams County Undersheriff Tony Spurlock. Groves served five years of a 12-year sentence for strangling 17-year-old Tammy Sue Woodrum and was released in February 1987. A jury convicted Groves of killing Diann Mancera and Juanita Lovato, a 1988 strangulation victim. Authorities have come to suspect Groves in anywhere from five to 13 murders, many involving prostitutes picked up along Colfax Avenue in Denver and Aurora.

DDNA evidence linked Billy Edwin Reid to the 1989 murder of Denver prostitute Lanell Williams. That case also led authorities to suspect him in the murder of Lisa Kay Kelley, whose body was found in March 1989 and wasn’t identified until 2005. Reid was convicted of murdering both women and sentenced to life in prison in 2008. Reid has also been linked to the murder of a third woman, Queena Sanders, and some officials believe Reid committed other murders.