AUGUSTA, Maine — The man charged with stabbing to death a 70-year-old local woman in 1976 pleaded guilty Friday in Kennebec County Superior Court to a charge of second degree criminal homicide, according to the Maine attorney general’s office.

Gary Sandford Raub, 64, a transient living in the Seattle area, was sentenced to 20 years in prison

He was arrested in October 2012 in connection with the death of Blanche M. Kimball, whose body was found in her State Street home in Augusta on June 12, 1976. An autopsy determined she had been stabbed multiple times.

Raub’s arrest set a record for the oldest cold case arrest in Maine history.

He entered an Alford plea to the charge. This type of plea — named for the U.S. Supreme Court case North Carolina v. Alford, decided in 1970 — is “a guilty plea that a defendant enters as part of a plea bargain, without actually admitting guilt,” according to Black’s Law Dictionary.

Raub’s plea agreement with prosecutors called for him to spend 20 years in prison, the mandatory minimum for the crime 38 years ago, when Maine classified criminal homicides in six degrees, according to Deputy Attorney General William Stokes.

First degree criminal homicide, the charge Raub initially was charged with, carried a mandatory sentence of life in prison if the prosecution proved the defendant knowingly inflicted great physical suffering on the victim, Stokes said Monday. The first degree charge was dropped after Raub pleaded guilty to a lesser charge.

Second degree criminal homicide was the equivalent of today’s murder charge, while the third and fourth degrees contained the elements of a manslaughter charge, he said. Fifth degree criminal homicide was a murder committed during the commission of a felony such as burglary, and the sixth degree was aiding or soliciting a suicide.

“It was highly complicated and was changed by the Legislature about 1977 to what we have now,” Stokes said.

Raub, who was going by the name Gary Robert Wilson at the time of the slaying, was extradited to Maine from Washington state on Jan. 25 and has been held without bail since then at the Kennebec County Jail. He pleaded not guilty to the charge Jan. 30.

He was tied to the cold murder case through DNA evidence after he took part in an undercover “chewing gum survey” in Seattle that police staged. He had rented a room from Kimball in 1976 and was the prime suspect in her murder from the beginning, according to the affidavit. Raub denied involvement in her death and left the state a few years after the murder.

He surfaced in fall 2012 in Seattle after he was suspected in the stabbing of another transient. Maine State Police Detective Abbe Chabot, who had taken over the cold case in 2003, worked with Seattle police to match blood from the knife used in the West Coast stabbing to blood found at the Augusta murder scene.

In July 2012, a Seattle police detective posed as a market researcher and asked Raub to participate in a “chewing gum survey,” for which he would be paid $5. Raub agreed, according to the affidavit. The gum he chewed was sent to the Maine State Police Crime Lab, where investigators concluded that the DNA matched a blood drop found on the kitchen drawer of Kimball’s residence after her murder.

BDN writer Alex Barber contributed to this report.