An almost 50-year-old cold case involving the double murder of a man and woman in Massachusetts may have had a significant breakthrough.

Authorities in Clearwater, Florida, arrested Timothy Scott Joley, 71, and charged him with two counts of homicide for the slayings of Theresa Marcoux, 18, and Mark Harnish, 20, who were found shot dead in 1978 near a highway in Springfield, Mass.

Joley, who has not yet made a plea in the case, was detained Oct. 30 after an unidentified person tipped off Massachusetts' Hampden District Attorney's Office earlier that month about the suspect's alleged involvement in the murders, DA Anthony Gullini said in a statement posted to Facebook Nov. 13.

Before his arrest, authorities say they matched Joley's fingerprints, kept on state file for almost 25 years, to a latent and seemingly bloody one found on the truck's passenger-side vent window during the initial crime scene investigation.

"Investigators obtained a fingerprint identification for Joley from the Springfield Police Department," Gullini told reporters at a Nov. 13 press conference, "which was on file with that department because Joley was fingerprinted as an applicant for a taxi cab license in the year 2000."

Marcoux and Harnish were both last seen alive in the early morning of Nov. 19, 1978, leaving a party hosted by friends. Hours later, a West Springfield Police Department officer on patrol found their bodies after observing Harnish's green 1967 Dodge pickup truck parked in a roadway rest area near Route 5.

"The officer saw that the driver's side window of the truck was damaged and noticed blood in and around the vehicle," Gullini said in the statement to social media. "The officer then discovered the remains of two individuals, one female and one male, just over a nearby guardrail."

He continued, "Investigators concluded that Theresa and Mark had been shot while in the passenger compartment of the pickup truck and their bodies were moved to the area where their remains were later discovered. Autopsies determined that the cause of death for each victim was multiple gunshot wounds."

While no firearm was ever located in or near the area, a nearby resident had reported to police hearing multiple gunshots at approximately 4:00 a.m. that morning and spent projectiles were recovered from the victims’ remains and the passenger area of the pickup truck, Gullini said.

The investigators, per the DA, determined that the fingerprint on the truck originated from Joley's left thumb and also learned that at the time of the murders, Joley was living in Springfield, was a licensed gun owner and had purchased a colt handgun approximately one month before the killings.

Joley remains in jail in Florida and is being held without bond ahead of his arraignment. No lawyer was listed for him in court documents obtained by E! News.

"On November 5, Joley appeared before a circuit judge in Pinellas County, Florida and waived extradition," Gullini said on Facebook. "Joley will be returned to Massachusetts in the coming weeks to face these charges."

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