Originally Published: 05 APR 22 19:20 ET

Updated: 06 APR 22 11:10 ET

By Dakin Andone, Amir Vera and Abby Bustin, CNN

(CNN) -- In the late 1980s and early 1990s, several women were murdered or sexually assaulted in a series of attacks at hotels along the Interstate 65 corridor in Kentucky and Indiana.

First, Vicki Heath was found dead at a Super 8 Motel in Elizabethtown, Kentucky, in 1987. Margaret "Peggy" Gill and Jeanne Gilbert were killed two years later at separate Days Inn locations in Indiana. Then, in early 1990, a Jane Doe was sexually assaulted at the Days Inn in Columbus, Indiana.

For decades, these attacks remained unsolved as investigators worked to piece together what information they had to identify a suspect.

Now they've succeeded after more than 30 years.

Harry Edward Greenwell, who died in 2013, has been identified as the killer behind the "I-65" or "Days Inn" cold case murders, Indiana State Police announced Tuesday, noting in a news release he had a long criminal history spanning from 1963 to 1998.

"To the family members that are here," ISP Superintendent Douglas Carter said in a news conference Tuesday, "I hope that today might bring a little bit of solace to you, to know that the animal who did this is no longer on this Earth."

Greenwell was identified through a process known as investigative genealogy, which involves uploading crime scene DNA to genealogy databases to find any genetic relatives and locate the offender through their family tree, according to the release.

Similar techniques have been used to identify suspects in other cold cases, perhaps most notably the case of the Golden State Killer.

In a news conference, Kim Gilbert Wright, the daughter of Jeanne Gilbert, thanked law enforcement for their work, saying her family was "extremely grateful" for their commitment to solving the case. But she also acknowledged justice and closure will look different to everyone affected.

"Some will believe the identity of the killer proves and provides justice -- the case is over -- while others will see justice as the moment a killer is convicted in a court of law and made to sit in prison thinking about the damage he's done to the families involved," said Gilbert Wright, who is an attorney.

"Some others might feel anger that the person has passed and is not able to face that trial and to face the peers that would judge him in his actions," she said. "And in our case, we'll never know what the killer was thinking, we'll never learn the whys of any of his actions. And that's just where we sit today."

Possibility other cases have yet to be linked

In the I-65 case, all four victims were attacked while working the night shifts at their respective hotels, according to ISP spokesperson Sgt. Glen Fifield.

Over the investigation, authorities collected evidence including ballistic evidence linking the Gill and Gilbert murders, Fifield said Tuesday. The ISP laboratory later matched DNA evidence linking the Heath and Gilbert murders to the Columbus case.

The victim in the Columbus case, the killer's only known surviving victim, was able to provide investigators after the attack with an "excellent" physical description of the suspect and the crime, Fifield said.

Citing recent advances in technologies, the ISP lab -- with the help of the FBI's Gang Response Investigative Team -- recently tested crime scene samples police say matched Greenwell's DNA with a close family member.

This match led to Greenwell's identification as a suspect, Fifield said. The match was 99.9999% positive, he said.

Greenwell, who frequently traveled throughout the Midwest, had an "extensive criminal history," Fifield said, noting the suspect was in and out of prison and even escaped from jail on two occasions.

While investigators have identified Greenwell as the suspect in the four crimes they laid out Tuesday, Fifield said law enforcement believe it is possible there are other murders, rapes, robberies and assaults yet to be connected to the killer.

I-65 runs from Mobile, Alabama, north to Gary, Indiana, and "investigators are actively working with other departments in the Midwest to determine if Greenwell was a perpetrator of other violent crimes yet to be solved," Fifield said.

In Tuesday's news conference, the leaders of various law enforcement agencies involved in the cases over the years praised the work and commitment of investigators. FBI Special Agent in Charge Herbert Stapleton also praised the bravery of the killer's surviving victim for providing law enforcement with crucial information to help solve the case.

"You never gave up," Stapleton said, "and I hope that today's announcement shows that this team of law enforcement agencies never gave up either."