A UPS driver out of work on disability is facing a felony murder charge after officials said he fatally shot his co-worker last week while the victim was on his route in Southern California.

Rhean Jalipa Fontanoza, 46, is accused of tracking down the driver and opening fire on him 14 times as the victim sat in the truck's driver seat striking him 10 times with projectiles, the Orange County District Attorney's Office wrote in a press release Tuesday.

Officials said Fontanoza is from Aliso Viejo, a city in the San Joaquin Hills of southern Orange County.

In a news release from the office, prosecutors identified the victim as 50-year-old UPS delivery driver Expedito De Leon and said, in addition to working with the victim, Fontanoza was the man's long-time childhood friend.

A motive in the shooting remains under investigation, officials said.

On Wednesday, UPS released the following statement to USA TODAY:

"We are shocked and saddened by the developments in Irvine. These are highly unusual circumstances and do not represent the culture of our company and the camaraderie among our employees around the world," the statement reads. "Our focus now is on supporting our people and their loved ones during this extremely difficult time."

Because the case was an open active and investigation Wednesday, UPS deferred additional questions to investigating officials.

USA TODAY has reached out to the DA's office.

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UPS employee hunted for coworker using computer that showed driver routes

According to a preliminary investigation, about 12:30 p.m. on Thursday, Fontanoza stopped another UPS driver and asked if the route belonged to his childhood friend, De Leon.

When the driver told him De Leon had another route, Fontanoza allegedly visited the UPS Aliso Viejo substation where he was seen "accessing a computer that shows driver routes and taking a picture with his phone."

At the time, prosecutors wrote, Fontanoza had been on disability leave but was scheduled to return to work on June 1.

Driving past victim in 'new vehicle he would not recognize'

Just before 3 p.m., the release continues, Fontanoza is accused of tracking De Leon down on his route and driving past him a new vehicle which De Leon "wouldn’t recognize."

De Leon then left his truck to make a delivery and returned to his truck, and buckled his seatbelt. The victim still held his UPS scanner in his hand and his seatbelt was buckled when Fontanoza drove next to De Leon’s delivery truck and shot him 14 times in 19 seconds, prosecutors reported.

The gunman drove away after the shooting. Fontanoza was found by police in his vehicle later that afternoon. He refused to exit his vehicle, prosecutors said, but was arrested after police deployed a K9 and tear gas into the vehicle.

Prosecutors charged Fontanoza with one count of special circumstance murder. He was jailed in Orange County with no bail on Wednesday, online records showed.

It was not immediately known if Fontanoza had obtained an attorney in the case.

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'Going about his day, just doing his job.

“Mr. De Leon was just going about his day, doing his job with no idea his longtime friend was stalking him with every intent to kill him,” Orange County District Attorney Todd Spitzer released in a statement Tuesday. “The depravity involved to plot and carry out a plan to execute someone you shared a lifetime of memories is not something anyone of us can wrap our heads around.”

If convicted of the felony charge, Fontanoza is eligible for the death penalty, prosecutors said.

The DA's office did not reveal whether prosecutors plan to seek execution if a jury finds him guilty in the case.

Natalie Neysa Alund is a senior reporter for USA TODAY. Reach her at [email protected] and follow her on X @nataliealund.