LOS ANGELES — A California man charged last year in a “serial thrill-kill” rampage that left six people dead, including four homeless men and a woman and her son, died Thursday after being found sick in his jail cell, an Orange County Sheriff’s Department spokesman said.

Deputies found Itzcoatl “Izzy” Ocampo, 25, ill in his single-man cell about 6:35 p.m. Wednesday at Central Jail in Santa Ana, said Lt. Jeff Hallock. Medical staff at the jail attended to him, and paramedics transported him to Western Medical Center in Santa Ana, Hallock said.

Ocampo was pronounced dead at the hospital about 1:30 p.m. Thursday, Hallock said. He said the cause of death was under investigation and that the probe would likely take several weeks. The Orange County District Attorney’s Office is investigating, as is routine with in-custody deaths, he said.

Orange County prosecutors were seeking the death penalty against Ocampo, who was scheduled to appear in court for a pretrial hearing in January. His death means that the relatives of those killed will not have the chance to see him held accountable, said district attorney’s spokeswoman Susan Kang Schroeder.

“It really deprives the victims and the people of California of the ability to put Mr. Ocampo to death on our terms and get justice for the victims of these crimes,” she said.

His defense attorney, Randall Longwith, said in an email that he would have no comment “until we learn all the facts.”

Last year, Longwith told the Los Angeles Times that his client had been behaving erratically and complained that he heard voices. He said Ocampo suffered from tics and headaches.

For months Ocampo went undetected, authorities said, as a string of killings occurred in North Orange County, starting with the stabbing death of his childhood friend and the friend’s mother on Oct. 25, 2011. Raquel Estrada, 53, and Juan Herrera, 34, were stabbed and left to die on the floor of their Yorba Linda home, prosecutors alleged.

The killings continued on the streets with the slayings of homeless men.

James Patrick McGillivray, 53, was killed near a shopping center in Placentia on Dec. 20, 2011. Several days later, Lloyd Middaugh, 42, was found dead near a riverbed in Anaheim. Paulus “Dutch” Smit, 57, was slain outside the Yorba Linda library on Dec. 30, 2011.

Police said Ocampo stalked a fourth homeless man, John Berry, 64, for several days after seeing his photograph in the Times. On Jan. 13, 2012, Ocampo ambushed Berry in a parking lot and stabbed him to death, authorities said. Police said a witness chased Ocampo into a nearby mobile home park, where he was captured.

He was accused of using the same Ka-bar Bull Dozier knife in the killings of all four homeless men.

Members of Ocampo’s family said after his arrest that they could not believe their loved one could be the killer who had struck such fear into the homeless population. They said the former Marine from Yorba Linda was generous to the homeless and frequently gave food and money to panhandlers.

But prosecutors said Ocampo would select homeless men and stalk them, waiting for the perfect moment to end their lives. He set a personal goal of 16 slayings, authorities said.

Ocampo told police after his arrest that he targeted the homeless because they were “available and vulnerable” and that he believed he was performing a public service because their presence was a “blight” on the community.

An Anaheim detective told grand jurors that Ocampo’s “demeanor would change, and he seemed to get excited” as he described the attacks to police. Ocampo told detectives he joined the Marine Corps in 2006 with the hope of learning to kill, but he was disappointed that during a six-month tour in Iraq he drove a water truck and never saw combat, according to the transcript of the grand jury hearing.

When Ocampo was asked what sort of consequences he deserved, the detective told grand jurors that Ocampo answered without hesitation: the death penalty — lethal injection — or “whatever is quickest.”

Distributed by MCT Information Services