A suspect has been arrested in a 40-year-old rape and murder case after he was identified through genetic genealogy, authorities in Colorado announced Monday.

James Curtis Clanton, 62, was charged with kidnapping and multiple counts of murder in connection with the killing of Helene Pruszynski, 21, on Jan. 16, 1980, Douglas County Sheriff Tony Spurlock told reporters.

Helene Pruszynski. Douglas County Sheriff

Investigators matched DNA recovered at the crime scene in Douglas County, south of Denver, with that of relatives of Clanton's who had been identified through public genealogy websites, NBC affiliate KUSA of Denver reported.

Dogged investigative work eventually led authorities to Union County, Florida, where Clanton was working as a truck driver, authorities said.

Investigators conducted surveillance on Clanton for six days, surreptitiously obtaining his DNA from a mug at a bar and matching it with the crime scene evidence, KUSA reported.

Clanton was arrested without incident and extradited to Colorado, authorities said.

It wasn't immediately clear whether he has a lawyer. He had not entered a plea Monday afternoon.

Download the NBC News app for breaking news

Spurlock said Pruszynski had moved from Massachusetts to Colorado two weeks before she was killed. She had hoped to be a journalist, and she was abducted and killed while returning home from her work as an intern at a radio station, Spurlock said.

"This is a young girl who was just starting her life," Spurlock said. "She wanted to be part of a bigger story."

When Douglas County District Attorney George Brauchler told Pruszynski's sister about Clanton's arrest, the emotion in her voice was still raw, he told reporters.

To hear that sound, he added, was "something special."