More than 40 years after 21-year-old Helene Pruszynski was brutally killed and left for dead in an area that is now Highlands Ranch, a man pleaded guilty to the crime.

James Clanton, 62, was slated to have a preliminary hearing but instead chose to waive his rights and pleaded guilty to first-degree murder in a Douglas County courtroom on Feb. 21.

Because of Clanton's plea, District Attorney George Brauchler announced the state would not seek the death penalty in the case. Instead, Clanton will receive a mandatory sentence of life in prison with the chance of parole after 20 years, Brauchler said. He will be formally sentenced April 10.

“At his age, if you asked me to guess, I'd say I don't expect him to make parole,” Brauchler said after the hearing.

Pruszynski's only living relative, her sister Janet Johnson, will make a statement at Clanton's sentencing hearing, Brauchler said, adding how emotional she was when she found out he would be pleading guilty.

“You can't imagine the kind of relief that would bring to a victim,” he said, “who I think had thought she would go to her grave not knowing who killed her sweet sister.”

Clanton's four other charges for the Jan. 16, 1980 crime, including sexual assault and kidnapping, were dropped as part of the plea agreement.

Pruszynski had recently moved to Colorado from Massachusetts for an internship with KHOW radio station when she was kidnapped near an Englewood bus stop while on her way home.

The next day, her body was found in a field near Daniels Park Road. She was naked from the waist down, with her hands bound. She had been stabbed multiple times.

Tracking a killer

The Douglas County Sheriff's Office was able to crack the case thanks to a new form of investigating that includes the use of DNA and genealogy.

Using a public database made up of profiles for those who have used genealogical testing programs, like 23 and Me and Ancestry.com, lead detective Shannon Jensen was able to find third and fourth cousins of Clanton based on DNA found on Pruszynski's body. Eventually, she was able to narrow it down to Clanton in mid-2019.

When she went into her supervisor's office to tell him what she found, she was shaking with adrenaline, she later said in an interview.

“It was pretty exhilarating,” she said. “I said `I know who he is.'”

This is the same investigative tool that gained media attention in 2018 when it was used to catch and prosecute the Golden State Killer in California.

“It gives new life to cases we once thought were unsolvable,” Jensen said.

A confession

Once Douglas County investigators had his name, they were able to track Clanton to Lake Butler, Florida, in November 2019, where investigators recovered a beer mug used by the suspect and matched the DNA to what was found at the crime scene, according to an arrest affidavit.

Then, investigators took it a step further. They knew Clanton could try to explain his DNA being found on the body by saying he had simply dated Pruszynski or even by challenging the accuracy of the technology, said Sgt. Atilla Denes of the Douglas County Sheriff's Office.

“We wanted to make sure that we eliminated those defenses by basically locking him into his story,” said Denes, who was the lead interviewer in the case.

The investigators decided to approach Clanton and tell him they were investigating a financial crime and possible identity theft from his time in Colorado.

After an hour of interviewing based on the false premise, they showed him a photo of Pruszynski. Clanton asked for an attorney.

When investigator told him they'd be arresting him for first-degree murder, he professed his innocence. Denes informed him they had his DNA and “his response was something like, `well, all right,'” Denes said.

From that point, Clanton was completely cooperative, according to investigators. He didn't fight extradition to Colorado and he fully confessed to the crime in Dec. 2019, even showing investigators where it all took place.

'A lot of remorse'

During the long flight back to Colorado, Clanton opened up about his crime and his own history.

“There was a lot of remorse, he shed a lot of tears.” Denes said. “He said that he felt that he had received many more years of freedom than he deserved.”

Out of all the suspects of violent crimes whom Denes and fellow investigator Lt. Tommy Barrella have dealt with in their careers, Clanton was unusual. He didn't blame the victim. He took full responsibility. He even apologized.

“He said every night he thought about her and her family,” Barrella said. “He said she didn't deserve what happened to her.”

One thing he said was grateful for is that he was able to raise his daughter, who is now 32.

“He was just thankful for that opportunity,” Denes said.

Clanton also opened up about his personal history. After being abandoned by his birth parents, he spent many years in foster homes where he endured sexual abuse, Denes said.

There's a possibility Pruszynski wasn't the last person Clanton attacked, Denes said.

“There could be additional victims,” Denes said, “but at this point, we don't have any direct evidence of that.”