A man prosecutors consider a serial killer and rapist pleaded guilty Tuesday to the 1973 murder of a Stanford Law librarian, the man’s second murder conviction aided by DNA evidence.

John Arthur Getreu, 78, admitted to killing Lesley Perlov, according to the Santa Clara County District Attorney’s Office. The plea comes 16 months after Getreu was convicted in the 1974 killing of another woman.

Prosecutors believe Getreu committed a string of sexual assaults and at least three slayings, two of which were part of a pattern in the 1970s known then as “The Stanford murders,” prosecutors said a news release.

Getreu was charged in 2018 with Perlov’s murder after investigators matched him to DNA found under her fingernails.

Perlov’s body was discovered in the hills that overlook the Stanford campus on Feb. 16, 1973. A floral scarf was found tightly knotted around Perlov’s neck and had been used as a ligature to strangle her to death.

“Justice for Leslie Perlov and her loved ones took a very long time, but it is has arrived,” District Attorney Jeff Rosen said in the announcement. “This serial rapist and murderer will spend the rest of his life in prison.”

Getreu’s sentencing is scheduled for April 26.

In a September 2021 verdict by a San Mateo County Superior Court jury, Getreu was found guilty in the killing of 21-year-old Janet Taylor, whose body was found along Sand Hill Road west of Interstate Highway 280 on March 25, 1974.

Taylor had been strangled and left along the roadside, according to the San Mateo County District Attorney’s Office. In that case, the jury deliberated for less than an hour before reaching its verdict.

Investigators in San Mateo County had reopened the case in 2017 and worked with their counterparts in Santa Clara County who were investigating Perlov’s killing.

Getreu was already in custody charged with the Perlov murder when San Mateo County investigators learned of a partial DNA match for him in the case against Taylor. When he was charged for the Taylor murder, investigators said Getreu had been put on trial in 1964 for rape resulting in the death of a 16-year-old girl in Germany when Getreu was 18 years old, and that he also had a conviction for raping a woman in Santa Clara County.