US police have identified the so-called “I-65 Killer”, also known as the “Days Inn Killer”, who murdered three motel clerks near a Midwest highway in the late 1980s.

Harry Edward Greenwell, who died aged 68 in 2013, has been named after testing of crime scene samples found a match that was “99.9999% positive”, Indiana State police said.

Greenwell was named the “I-65 Killer” because he sexually assaulted and shot dead three women at motels near the major north-south Interstate 65 highway in the central US.

Indiana State Police Sergeant Glen Fifield said in a joint news conference with the FBI on Tuesday: “Greenwell had an extensive criminal history and had been in and out of prison several times, even escaping from jail on two separate occasions.

“He was known to travel frequently in the Midwest.”

Sergeant Fifield said both genealogical data and crime scene evidence were used to identify Greenwell after a 30-year search.

The first killing took place in February 1987 when Vicki Heath was sexually assaulted and shot in the head while working a night shift at the Super 8 Hotel in Elizabethtown, Kentucky.

Police said the evidence also linked Greenwell to the 1989 sexual assaults and murders of Margaret “Peggy” Gill and Jeanne Gilbert in Indiana.

Ms Gill was working at a Days Inn in Merrillville when she was killed, while Ms Gilbert was working at a Days Inn in Remington.

Sergeant Fifield said investigators also linked Greenwell to the sexual assault of a 21-year-old female clerk at a Days Inn in Columbus, Indiana in January 1990.

“This victim was able to escape her attacker and survive. She was later able to give an excellent physical description of the suspect and details of the crime,” the police sergeant said.

“She is the only known victim to have survived the vicious, brutal attacks of this killer.”

The woman described her attacker as a man with green eyes and said the right one was lazy, NBC News affiliate WTHR of Indianapolis reported.

Sergeant Fifield said the Indiana state police crime lab matched ballistic evidence related to the murders of Ms Gill and Ms Gilbert.

Police later matched DNA evidence linking the deaths of Ms Heath and Ms Gilbert to the attack in Columbus.

Sergeant Fifield said one of the primary factors linking the four crimes was their proximity to Interstate 65, which runs from Gary, Indiana, to Mobile, Alabama.

The police sergeant also said investigative genealogy, the use of DNA analysis in combination with traditional genealogy research and hospital records “generated a significant and important lead” in the four cases.

Sergeant Fifield continued: “Further investigation and kinship lab testing by the Indiana State Police lab of crime scene samples positive identified the suspect.

“The match was 99.9999% positive.

“It is this scientific breakthrough that ultimately led to the identification of the I-65 killer, Harry Edward Greenwell.”

Sergeant Fifield said investigators are continuing to reach out to other police departments in the Midwest because there is a “distinct possibility” that Greenwell committed other unsolved killings, rapes, robberies or assaults.

Kimberly Gilbert Wright, Ms Gilbert’s daughter, said at Tuesday’s news conference that her family was grateful for the police’s efforts to identify her mother’s killer.

“She’s still in my family’s hearts,” she said of her mother. “We talk about her as if she hasn’t gone. My brother and I were fortunate enough to have spent the last seven months of her life living with her and experiencing the joy that she could bring to every day of our life.”

Greenwell was born in Kentucky and died of cancer in Iowa, according to an obituary that was published after his death.