Jaime Osuna smirked, smiled and waved at the family of Yvette Pena as he was jailed for life for the 29-year-old Californian woman's brutal torture and murder.
Dressed in a green prison uniform with tattoos covering his face, the killer wanted everyone to know he not remorseful. He even shot the judge a thumbs up.
The display inside Kings County Superior Court, halfway between Sacramento and Los Angeles, was an insight into Osuna's state of mind.
But nobody could've foreseen just how twisted he would become.
Last month, less than two years after he was jailed, Osuna allegedly committed a crime that one local prosecutor called the "most gruesome" he has ever seen.
According to local reports, Osuna, now 31, allegedly used a sharp metal object wrapped in string and attached to a handle to torture his Corcoran State Prison cellmate, Luis Romero, 44, before beheading him.
He is accused of cutting off several of Romero's body parts, including a finger and part of a lung, before removing an eye and cutting off Romero's head.
Authorities say they do not know how much of the attack took place while Romero was still alive.
Assistant Kings County District Attorney Phil Esbenshade said on Friday that "we do believe the victim was conscious during at least a portion of the time" and "this is the most gruesome case that I have seen in terms of heinousness in the slaying".
Esbenshade said the weapon was allegedly located inside Osuna's cell and "looked like it had been fashioned from some of razor that may have been issued".
Osuna pleaded not guilty to murder, torture, mayhem and weapons possession this week, and if found guilty he could face the death penalty.
Luis Romero was murdered inside his cell. Photo / AP
The charges allege Osuna repeatedly cut Romero to cause cruel and extreme pain and suffering for a sadistic purpose.
The California Department of Corrections and Rehabilitation is conducting an internal investigation into how the murder took place without guards being alerted.
Corcoran State Prison, formerly home to Charles Manson, is a male-only facility with a capacity for more than 3000 inmates. According to a 1996 report in the Los Angeles Times, the facility was run by out-of-control guards who tortured inmates.
"It was common practice for guards to pair off rival inmates like roosters in a cockfight, complete with spectators and wagering, then sometimes shoot those who wouldn't stop fighting," the report reads.
"Shackled inmates arriving from other prisons were pummeled (sic) by officers in an intimidation rite called 'greet the bus,' they say. Other inmates were forced to stand without shoes on scorching asphalt, their severe burns blamed on games of barefoot handball."
Warden at the time, George Smith, told the newspaper that not all staff were out of control, but a few were.
"I'll admit that some of my staff have gone crazy," Smith said. "But it was only a few who screwed up. We've got 1700 good employees."
Osuna first made headlines in 2011 when he murdered Pena at a motel in Desert Hot Springs, an hour and 40 minutes east of Los Angeles.
Pena's body was found on November 13, 2011 at the El Morocco Motel. She had suffered during the hours before she died from sharp-force injuries, blunt trauma injuries and asphyxia, according to The Bakersfield Californian.
Prosecutor Nicholas Lackie called her murder "truly horrific", but Osuna refused to show remorse.
Danielle Gonzales, Pena's younger sister, said Osuna smiled regularly during a dozen court appearances before he was sentenced.
She said she still feels as much pain as she did when she first learned about her sister's murder.
