California correctional officers discovered the serial killer known as the “I-5 Strangler” dead inside his cell on Sunday in what authorities believe is a homicide case.

Authorities found the body of 81-year-old Roger Kibbe, who was arrested for the rape and murder of at least seven women, at around 12:40 a.m. on Sunday. Correctional officers were conducting an institution population count at Mule Creek State Prison when they discovered the deceased.

Murderer Found Dead

The California Department of Corrections and Rehabilitation said officers found Kibbe’s cellmate, 40-year-old Jason Budrow, standing in the next cell when they discovered the dead body.

“Medical staff immediately responded to the incident and transported Kibbe to the institution health care facility for higher level of care. Life-saving measures were unsuccessful, and Kibbe was pronounced deceased at 1:23 a.m. by institution medical staff,” said officials.

Since his arrest, Kibbe was given multiple life sentences after a series of murders between the 1970s and 80s targeting women and girls. The convict routinely cut his victims’ clothing and hair using scissors and kept them as memorabilia.

The deceased’s cellmate, Budrow, was also serving a life sentence without the possibility of parole for first-degree murder, said officials. While authorities continued to investigate Kibbe’s death, they transferred Budrow to the administrative segregation unit.

Officials convicted Kibbe in 1991 after his 1987 strangling of a 17-year-old girl named Darcine Frackenpohl, who ran away from her home. Later, six other murders were linked to him in the early 2000s with the use of DNA technology.

Kibbe pleaded guilty to the additional murder counts with special enhancements for rape and kidnapping in 2009 and was given consecutive life sentences in exchange for not being given the death penalty.

The first known crime Kibbe committed was the murder of 21-year-old Lou Ellen Burleigh in 1977. The victim suddenly disappeared after a job interview at a Pleasant Hill shopping center for a cosmetics job position.

Before her disappearance, Burleigh told her family she met a man who said he worked at the shopping center. He said that the building was under construction, so they had to do the interview inside his van. While the victim was anxious about the situation, their first meeting was uneventful. But on their second meeting the next day, Burleigh did not return home.

Later, Kibbe confessed to tying the victim up, driving her to Lake Berryessa, raping her, and lastly, killing her. Authorities discovered a bone fragment of Burleigh in 2011 after the murderer revealed where he disposed of her body.

Authorities also linked Kibbe to the murder of five other women in 1986. The victims were Barbara Ann Scott, Stephanie Brown, Charmaine Sabrah, Katherine Kelly Quinones, and Lora Heedrick.

Officials discovered Heedrick’s body on September 6, 1986, about five months after Burleigh was last seen. They also found the body of 19-year-old Brown in July 1986 with signs of being strangled and sexually assaulted, Oxygen reported.

Reports of Sabrah’s disappearance were first called in after she was last seen on August 17, 1986, when her car broke along I-5. she accepted to be a passenger of a man in a two-seater sports car, leaving her mother behind. Police later found her dead body strangled with her tank top in November of that year.

Authorities said Frackenpohl was murdered the next year when she was strangled with the use of a cord with dowels on both ends. Police later found the murder weapon inside Kibbe’s storage locker.