The man accused of slashing five coworkers in a bloody rampage sported a menacing stare as prosecutors revealed disturbing new details about his alleged evil act.

Joseph Naugle, 22, wore an anti-suicide vest as he was wheeled into a Placer County courtroom Friday to face charges in the shocking Thunder Valley Casino Resort attack that left bloodied victims sprawled among slot machines Wednesday night.

Naugle glared around the room as he was charged with three additional felony accounts in addition to the two counts of murder he was already hit with by Placer County District Attorney Morgan Gire.

The additional charges included one count of assault with a deadly weapon by knife and two counts of assault by means of force likely to produce a great bodily injury.

Naugle did not enter a plea. He is due back before a judge next week.

Naugle intentionally planned the two attempted murders by knife that he allegedly committed against his coworkers at the Dos Coyotes Border Cafe inside the popular casino, according to Gire.

“The complaint charges two counts of premeditated and willful attempted murder based on the conduct that occurred in the kitchen area,” said Gire. “It was a predetermined intent to kill.”

The DA said the reasons behind Naugle’s alleged slashing spree were still being investigated.

“In terms of his motive or reasons why he chose to do this, I can’t speculate on that at this point,” said Gire.

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The accused slasher is being held without bail at Southern Placer Jail. Gile said he would seek to have the defendant kept in custody for the duration of his trial.

The accused mass stabber might’ve injured many more people had not some of his coworkers stepped in to subdue him, the DA said.

“This could have been much worse, but for the incredibly heroic acts of some Thunder Valley casino employees,” said Gile.

The mayhem at Thunder Valley unfolded Wednesday night when Naugle, a kitchen worker at Dos Coyotes inside the casino, unleashed his knife attack on his fellow employees in the popular eatery’s kitchen area.

Shocked gamblers looked on in horror as bloodied victims spilled out of the restaurant and onto the casino floor. A caller reported the incident to police, who arrived within minutes and immediately took Naugle into custody.

One victim was transported to a hospital with non-life-threatening injuries, while the four others were treated at the scene by Thunder Valley emergency personnel and Cal Fire. The hospitalized victim was released hours later after receiving emergency treatment.

None of the victim’s injuries were life-threatening.

Naugle, who was still dressed in his kitchen apron when he was arrested, is a Roseville resident who graduated from a local high school in 2022.

Police collected numerous statements from witnesses and victims at the crime scene. Security camera footage is also being reviewed by investigators, Gile said.

“Video surveillance is a critical component to this case and allows us to sort of see exactly what happened as it unfolds,” he said.

Naugle had only been an employee of the casino for about six weeks at the time of the attack, the DA said.

Dos Coyotes was closed following the attack, but the casino floor remained open for gamblers.

It was back to business as usual for Thunder Valley Thursday night, about 24 hours after Naugle’s alleged attack.

The casino got back to “partying non-stop,” with patrons vibing with “24-karat magic in the air.”

Just hours after blood had dried on the casino floor from the stabbing spree, the casino’s official account posted on social media about a Bruno Mars tribute concert.

“We were partying non-stop tonight at The Venue with 24K Magic – Tribute to Bruno Mars!” the Thursday post on X said.

The casino made no mention of the stabbing on its social media page.

The Post reached out to Thunder Valley for comment.