SAN FRANCISCO – Colleagues and researchers were at a loss Thursday to explain what the cause of a San Francisco UPS driver to pull out an assault weapon at work and for the killing of three people who the police suspect that he targeted.
Jimmy Lam, an 18-year veteran of UPS, was published one of the three slain drivers, but investigators have yet to determine what for him on Wednesday, an official of the San Francisco Police Department said.
The official was not authorized to discuss the case publicly and spoke on condition of anonymity.
The violence came to an end when the 38-year-old Lamb turned the gun on himself and took his own life as an employee, ran from the packaging facility, and the police closed.
As researchers worked to determine a motive, friends and colleagues told personal and professional problems that Lamb had ever experienced, including a number of driving violations.
He was convicted twice of driving on a suspended license in 2013 and 2014, according to the DMV records. His license was also suspended in 2014 negligent for operating a vehicle.
Lamb also had a run-in with the law in 2010, when he was convicted in San Francisco of driving under the influence and sentenced to three years conditionally.
UPS spokeswoman Susan Rosenberg said that she did not know details about the Lamb of the driving record and would not comment. They added, however, that UPS drivers are expected to be able to drive legally.
There was no indication that the Lamb of the row-record has affected his ability to work at UPS.
In another case, Lam filed a complaint in March claiming that he was working excessive overtime, said Joseph Cilia, Lamb, a friend of an official with the union that represents UPS drivers. George said the Lamb was angry with the managers, whom he accused of forcing him to work overtime.
But none of the men who were shot were managers, Jess noted, adding that he knew of no disputes between the Lamb and the victims.
Shaun Vu, a senior UPS driver, said Lam struggled with depression and had personal problems of a few years ago involved in a dispute with a friend about the access rights for their young child. Vu said he encouraged Lam to seek counseling.
“I told him, that you have a problem or feel bad about yourself or your life, the best thing to do is to seek professional help,” he said.
Lamb told Vu that he would speak with the management, and then went to work for a number of months. He seemed fine when he returned to work, but the Vu saw a few weeks ago that Lamb looked amazing.
“I saw him, and asked how he was doing,” Vu said. “He said something like,” I’m stuck.’
“I do not think that he had nobody who he could talk to, and it got worse and worse,” Vu said.
Lamb was an AMERICAN citizen who immigrated to the United States as a baby from Thailand, said Sharon Rummery, a spokeswoman for the U.S. Immigration and Citizenship Services. She refused to comment further.
The researchers said it remained a mystery to them why Lamb went to the co-workers he had known for years.
Determining the motivation behind the violence at the workplace may take a while, say the experts.
“What seems to be from violence in the workplace can also be something else,” said Chuck Wexler, director of the Police Executive Research Reform, a Washington D. C. on the basis of police investigation group.
“That is the reason why the police really need to look deeper into the person and the background,” he said.
The shooting happened during a morning planning meeting for drivers on delivery routes.
Jess said witnesses told him that the Lamb ran to the driver Benson Louie and shot him during the meeting. As his staff frantically fled the room, he shot Wayne Chan in the back and then ran, and “done with him,” Jess said, referring to witnesses.
Victim Mike Lefiti was fleeing from the building, when the Lamb went to a street and shot him, ” he said.
Lefiti, 46, and Louie, 50, had each worked for UPS for 17 years, according to the company. Chan, 56, had 28 years of service.
UPS workers are paid respect for the victims at a memorial erected at the packaging facility where the shooting had occurred a day earlier. People said prayers and signed a poster in honor of their three old colleagues.
Vu described Chan as an expert-it-yourselfer would come at any time to help him build a fence or repair an electricity outlet. Chan leaves a wife and two children.
Tribute is also paid on social media for Louie, who was considered a legend in the nine-man volleyball, a version of a game brought by Chinese immigrant laborers who played in the streets. He left a wife and two daughters.
Mamie Wong said that she had known Louie since she was in high school.
“He had a big, generous heart,” she said. “He would bend over backward for you. If you need a place to stay, he would give you a place. If you needed a car to drive, he would give you a car.
“He left a big hole in our hearts.”
AP writers Sudhin Thanawala and Jocelyn Gecker contributed to this report.