A serial killer sentenced to death for a dozen murders in Southern California more than three decades ago confessed to another killing after his DNA was linked to the victim, authorities said Tuesday.

Los Angeles County sheriff’s officials identified the victim as Cathy Small, 19. She was found unresponsive on a South Pasadena street on Feb. 22, 1986, and was later determined to have died from stab wounds and strangulation, Sheriff’s Lt. Patricia Thomas told reporters.

The confessed killer, William Lester Suff, 73, is incarcerated at a substance abuse treatment facility north of Los Angeles, state prison records show. His trial lawyers did not immediately respond to emailed requests for comment Wednesday night.

Cathy Small.Los Angeles County Sheriff’s Department via Facebook

Small’s killing remained unsolved until a coroner’s official investigating the natural death of a 63-year-old man in South Pasadena five years ago found disturbing images and a newspaper article about Small’s killing at the man’s home, Thomas said.

The coroner’s investigator alerted the sheriff’s office, and authorities initially believed the 63-year-old man was most likely responsible for Small’s killing, Louie Aguilera, the lead detective on the case, told reporters.

But a DNA analysis found that the mans DNA did not match genetic material obtained from Smalls clothing or a sexual assault kit test conducted on the victim after her death, Thomas said.

However, there was a match with Suff, who was then on death row at Californias San Quentin prison for the murders of 12 women from 1989 to 1991, Thomas said.

At the time of the killings, Suff was on parole for the 1974 murder of his 2-month-old daughter in Texas, Thomas said.

Like Small, Suffs other victims were sex workers, according to a Los Angeles Times account of his 1992 indictment. He was charged in the killings after a woman escaped an attack in 1989 and identified him in a photo lineup, according to the newspaper.

Suff, who was convicted in 1995, became known as the “Lake Elsinore Killer” and the “Riverside Prostitute Killer,” references to the locations of the killings in Riverside County, east of Los Angeles, Thomas said.

At the time of her murder, Small, a mother of two, was living in the Lake Elsinore area. Her roommate told authorities that she left home on the night of Feb. 21 and planned to drive to Los Angeles with a man named “Bill” for $50, Thomas said.

“He never saw or heard from her again,” Thomas said.

After Suffs DNA was identified as a source of genetic material in the killing, Thomas said, he agreed to be interviewed by authorities and talked to detectives from the sheriffs office for more than seven hours.

Suff told them that at the time of the murder, hed been working at a computer repair shop in Riverside County. Small met him there and gave him her phone number, Thomas said.

Suff told investigators that on Feb. 21, 1986, he called Small and asked her to go to Los Angeles with him to pick up his boss, Thomas said. She agreed, and he picked her up at 10 p.m., according to Thomas.

Suff told investigators that after they arrived in Pasadena, they got into an argument and that he stabbed Small multiple times after she knocked the glasses off of his face, Thomas said.

Suff said he pushed her onto the street and left her there, according to Thomas.

Thomas said the sheriffs office presented the case to the district attorneys office for declination purposes only because of Suffs prior convictions and death sentence. (Gov. Gavin Newsom halted executions in California in 2019, citing wrongful convictions of people condemned to death in the state.)

In a statement provided to the sheriffs office, Smalls younger sister said her sister was “not a statistic” and described her as a protective and talented big sister who taught her to swim, ride a bike and play cards.

“She was seeking sobriety when I last saw her,” the sister said in the statement. “Although I was only 10, I knew my sister was working hard to put her life back on the right tracks.”

The sister said she didnt know why Small chose to go with Suff, according to the statement. She said shed spent her life trying to figure who killed her sister.

“I think of her every day,” she said in the statement. “Only because of detective Aguilera do I now have answers.”