ANAHEIM -- The man suspected of killing two Southern California Gas Company workers has died several days after being found in his car with a self-inflicted gunshot wound to the head, police said.

Phong Thuc Tran, 36, of Orange County, died Saturday night at the UC Irvine Medical Center, according to Anaheim Police Sgt. Tim Schmidt.

Tran was found in a parked SUV outside an Anaheim police station around 1:30 a.m. Thursday with a self-inflicted gunshot wound to the head, according to Sgt. Rick Martinez of the Anaheim Police department.

The suspect's gray 2007 Toyota Rav4 was spotted on Santa Ana and Harbor Boulevards by an officer driving in the area.

The vehicle's window appeared to be broken, prompting the officer to investigate, Martinez said.

The vehicle matched the description given to police after the shootings in Pomona and Anaheim.

Officers took a defensive stance while trying to coax the suspect out of the vehicle. They eventually fired beanbag rounds and pulled him onto the ground. Tran was taken to a local hospital in critical condition.

Police believe Tran may have shot and killed two men who worked for the same gas company he once worked for, officials said.

The killings took place miles apart, within just a few hours.

The first victim was found in his personal vehicle about 10:30 p.m. Tuesday in the Gas
Co. lot at 1919 S. State College Blvd., said Anaheim police Sgt. Tim Schmidt.

He has been identified as Hung Duy Dao, 37, of Westminster, a field technician who had worked for the company about six or seven years.

The second victim was found a few hours later in Pomona.

Charles Rene Santisteban, 43, was found outside his house in the 300 block of East La Verne Street.

Santisteban's body was in the driveway, "like he had just gotten out of his car and was walking to his doorway, like he just arrived home," Schmidt said.

Schmidt said the two shooting victims worked together at the Anaheim site until about six months ago when Santisteban, who was a supervisor, was transferred to Pasadena.

Both victims were shot multiple times, Schmidt said.

Investigators say Tran worked for the Southern California Gas Company and resigned for unknown reasons in 2007. It's not yet known which two additional employees he allegedly planned to kill.

Police believe the slayings were related to Tran's resignation, officials said.

The utility company issued a statement promising to cooperate in the investigation and calling it a "sad day at the Southern California Gas Company."

"We've lost two of our co-workers and friends. We want to express our sincere sympathy to the families of the employees," the statement says.

"The safety of our employees and customers is our top priority. We are doing all that we can to assist authorities in their investigation."

Officers recovered two handguns from Tran's vehicle, Martinez said, adding that they will be tested against the slugs taken from the two homicide victims to see if there is a match.

Anyone with information about the shootings was asked to call (714) 765-1900.