Sacramento, California (AP) – Authorities say a prolific serial torture killer known as a “date game killer” died on Saturday while awaiting execution in California. Rodney James Alcala died at the age of 77.

Prison officials said in a statement that he died of natural causes in a hospital in San Joaquin Valley, California.

Alcala was sentenced to death in 2010 for five murders in California between 1977 and 1979, including a 12-year-old girl, although authorities estimate that he may have killed as many as 130 people across the country.

After pleading guilty to two homicides in New York in 2013, Alcala received an additional 25 years of life.

He was charged again in 2016 after DNA evidence linked him to the death of a 28-year-old woman found in a remote area of ??southwestern Wyoming in 1977. However, a prosecutor said that Alcala was too ill to accept the trial of the woman’s death. She was six months pregnant when she died.

California’s death row is in San Quentin State Prison near San Francisco, but Alcala has been held in Corcoran Prison more than 200 miles away for many years, where he can receive medical care around the clock.

Prosecutors said Alcala stalked women like prey and took earrings from some of his victims as trophies.

Attorney Matt Murphy of Orange County, California, said during the trial: “You are talking about a man hunting in Southern California, because he likes to kill, so he likes to kill.”

Investigators said that the number of his true victims may never be known.

The earrings helped put him on death row, even though Governor Gavin Newsom has suspended executions as long as he is the governor.

The mother of 12-year-old Robin Samsoe testified in his murder trial that the pair of golden ball earrings found in the jewelry bag in the Alcala locker belonged to her daughter.

But Alcala claimed that the earrings belonged to him, and a video clip that appeared in the “Dating Game” in 1978 showed that he wore the earrings nearly a year before Samsoe’s death. He denied the killing and cited inconsistencies in the witness’s statement and description.

California prosecutors said Alcala also took earrings from at least two of his adult victims as trophies.

Prosecutors said that two of the four women were naked after death, one was raped by a claw hammer, and all of them were repeatedly strangled and resuscitated to prolong their pain.

Investigators said that the DNA of a victim was found on the rose-shaped earrings owned by Alcala and his DNA was found in her body.

Before the murder of Samso, he was sentenced to death twice, but both convictions were overturned. More than two decades later, based on new DNA and other forensic evidence, he was accused of killing four adult women.

After the verdict, the authorities released more than 100 photos of young women and girls owned by Alcala, hoping to link him to other unsolved murders across the country.

“There was murder and rape, and then there was a clear massacre of Rodney Alcala-style murder,” said Bruce Barcomb, the brother of the 18-year-old victim Jill Barcomb, when he was sentenced to death in Alcala.