Police Study Motives for Hospital Shooting

The man accused of fatally shooting three Orange County hospital workers hours after his mother died was acting out of irrational grief, police said Wednesday, and a preliminary investigation found no evidence that the 72-year-old woman was mistreated by employees.

“We can’t determine that ‘Dr. A’ did something that led to his mother’s death,” said Anaheim Police Sgt. Joe Vargas. The deadly shooting, he said, was the result of “irrational and misguided motive--and that is revenge for his mother’s death.”

The suspected gunman, Dung Trinh, carried dozens of rounds of ammunition when he entered the West Anaheim Medical Center on Tuesday morning, detectives said. They believe he would have shot many more people had he not been disarmed by one of his victims, Ronald Robertson.

“Had it not been for Mr. Robertson . . . detectives feel that there would have been additional casualties in this case,” Vargas said. “He really did a job. It’s amazing when seemingly ordinary people rise to the top.”

Police said they are focusing their investigation on the five hours between the time Trinh’s mother died at a nearby hospital and the late morning rampage that began with the attacker shouting, “You killed my mother!”

Authorities said that Trinh had time to plan the attack and arm himself.

Under California law, jurors can decide that a killer acting in the “heat of passion” is guilty of voluntary manslaughter, which carries a maximum penalty of 11 years in prison. Premeditated murder can lead to a death sentence.

Trinh, an unemployed chef from Anaheim, lived with his ailing mother in a one-bedroom Anaheim apartment. She suffered from diabetes and had been in a wheelchair after breaking her hip this year.

Police said they are skeptical of Trinh’s allegations that his mother was mistreated. She is believed to have died of heart disease. She had been a patient at West Anaheim Medical Center in May for hip replacement surgery.

“We will be looking at motivating factors,” Vargas said. “But at this point, it doesn’t matter what the motivation was--it’s a homicide.”

Hospital officials, meanwhile, said they would launch their own investigation into Mot Trinh’s medical care.

“I think it’s fair to review the chart,” said Dr. Hwa Lee, chairman of the internal medicine department.

Although police said they remain unsure whom the gunman was targeting during the shooting rampage, a top hospital official said that Dung Trinh was intent on killing a nurse who had cared for his mother during her hip replacement surgery this spring.

Relatives of the nurse said Wednesday that she was in seclusion, having seen a colleague shot and killed. “She’s doing how anybody else would be doing if someone died in front of them,” the woman’s daughter said.

Patients and workers arrived at the hospital Wednesday amid tightened security. Guards, some of them armed, stood at the building’s entrances, clad in bulletproof vests.

“It’s an odd feeling to walk here where something that violent happened,” said Karen Gardner as she arrived with her mother for medical tests. “I won’t live in fear. You can’t live in fear.”

Grief and crisis intervention counselors, some sent from nearby hospitals, tended to employees and patients traumatized by Tuesday’s shooting.

“We’re looking for signs that the employees are . . . stressed,” said hospital spokeswoman Debra Culver.

Police remain unsure exactly what time the gunman arrived at the medical center.

But at 10:45 a.m., police said, he went to the nurses’ reporting room on the second floor, where he shot and killed nursing assistant Marlene Mustaffa.

Mustaffa was standing near the nurse hospital officials believe was the gunman’s target, said Dr. Robert McCauley, a staff internist.

Authorities gave this account of what happened next:

The assailant left the room and made his way down the hall to the stairwell, armed with a revolver. Terrified patients and workers dived for cover. The gunman pointed at people, but did not shoot.

At a stairwell, he met Vincent Rosetti, the hospital’s director of pharmacy. Rosetti, police believe, was responding to a call for assistance made before the first shots. He lunged for the revolver, but was fatally shot during the struggle.

The gunman walked down the stairs, police said, perhaps reloading one of his snub-nosed revolvers with ammunition he carried in a shoulder bag. When he reached the first floor, he headed toward the lobby, where Robertson was frantically trying to close the automatic double doors separating the gunman from the crowded lobby.

A shot was fired. Robertson, already wounded, rushed the gunman. During the struggle, two revolvers fell to the floor. Two men jumped in and held the suspect until police arrived.

Robertson was struck twice in the chest and once in the neck. He was rushed to the emergency room, where doctors struggled for more than an hour to save him.

“One of our investigators was in the ER room at the time, and he said it was one of the most emotional scenes he’s ever seen,” Vargas said.

Neighbors of Robertson recalled how the Vietnam War veteran lived for his family, particularly for his three teenage children.

“He was a hero to his family, now he’s a hero to everyone,” said Carolyn Turner, who has lived in the same Fullerton neighborhood as Robertson for more than two decades.

In the Vietnam War, Robertson suffered wounds to his stomach and was hit in the eye by shrapnel, Turner said. Another wound left him without sensation in his left arm below the elbow, she said. Robertson, the hospital’s director of environmental services, regularly flew the national flag outside his house along with a second one honoring soldiers missing in action.

He was raising a daughter, 13, and two sons, ages 15 and 17, Turner said. After work, he was often outside playing baseball or soccer with one of his children. His daughter learned of the shooting on TV news.

“It’s a bummer, especially for the children,” said another neighbor, Dave Eminhizer. “They are at a time when they need their dad the most. . . . He was always on the go.”

Trinh is expected to be arraigned today on murder charges.

Because there are multiple victims in the case, a murder conviction could bring Trinh the death penalty, said Deputy Dist. Atty. Chris Kralick.

Times staff writers Jennifer Mena and Jeff Gottlieb and correspondents Louise Roug and Jason Kandel contributed to this story.