A DNA sample from a phony "chewing gum survey" led to the arrest of a man who has been charged with killing a 70-year-old woman in 1976, making this the oldest cold case to ever be cracked in Maine.

Gary Sanford Raub, 63, was arrested on Monday in Seattle and charged with murdering 70-year-old Blanche Kimball in Augusta, Maine.

Kimball was found stabbed to death inside her State Street home on June 12, 1976 after neighbors called police to say they had not seen her for several days. The killer eluded investigators and the case turned cold, but authorities kept at it over the decades.

"In Maine, State Police assign the open homicide cases to a detective. There's always a detective assigned to these cases, which are constantly reviewed, as time permits," Maine State Police spokesman Steve McCausland told ABCNews.com.

Recent DNA work by the State Police Crime Lab on evidence from the crime led them to Raub, authorities said.

"It was last summer that we got some very concrete DNA work on some of the evidence that was seized and made a comparison that brought us to this point," McCausland said. "It was DNA that cracked this."

Raub was tracked to Seattle, where he was living as a homeless transient and police knew him from his lengthy criminal record. Authorities discovered that Raub knew Kimball and had at one time lived at her home.

Augusta investigators coordinated with authorities in Seattle and used a fake "gum chewing survey" to get a new DNA sample from Raub.

"I don't know the exact details, but we obviously needed some up-to-date DNA from him and some bubble gum was the key to getting that," McCausland said.

Three decades later, investigators remained committed to finding justice for Kimball.

Continued here:
Fake 'Gum Survey' DNA Solves Case