SAN FRANCISCO (KTVU) -- As police investigate what prompted a UPS worker to open fire Wednesday and kill three of his co-workers before turning the gun on himself, new details began to emerge about the moments leading up to the shooting at the San Francisco facility.
Six people in all were shot in a case that was reported at 8:55 a.m. at the UPS facility at 320 San Bruno Ave. at 17th Street, Assistant Chief Toney Chaplin said.
The gunman has been identified as Jimmy Lam.
The three victims, all UPS drivers, who were killed were also identified by the San Francisco Office of the Medical Examiner and next of kin has been notified. Their names are Wayne Chan, 56, of San Francisco, Benson Louie, age 50, a resident of San Francisco, and Michael Lefiti, 46, of Hercules.
Responding officers found shooting victims at the scene and moved them to safety for medical treatment, then encountered the suspect dressed in a brown UPS uniform. The suspect put a gun to his head and shot himself, Chaplin said. He said investigators haven't determined a possible motive for the shooting.
Sources told KTVU FOX 2 News that UPS drivers meet briefly every day around 8:45 a.m. to discuss workplace issues. At Wednesday's meeting, Lam was angered by something said to him and he went to his car to retrieve his weapons. When he returned to the building, he opened fire on his co-workers.
Chaplin said authorities would not release the names of the three victims who were killed or publicly identify the gunman who took his own life until the medical examiner confirms their identities and families are notified.
Family members earlier had identified one of the victims as 46-year-old Mike Lefiti, a UPS driver.
Lefiti's cousin, Bob Toia, told the San Francisco Chronicle that Lefiti was devoted to his wife, family and kids.
Isaiah Miggins, a co-worker of Lefiti's at UPS, said Lefiti was a big man, but humble and always happy.
By late afternoon, friends had set up a memorial to Lefiti with flowers and balloons at a local supermarket near the UPS warehouse.
Police say a gunman opened fire at the UPS facility Wednesday morning, killing three people and wounding two others before taking his own life.
UPS spokesman Steve Gaut said about 350 employees work at the facility at 320 San Bruno Ave., which operates as a package sorting hub and delivery center.
Gaut said, "The company is saddened and deeply concerned about affected employees, family members and the community we share."
San Francisco Mayor Ed Lee also issued a statement, offering "condolences and thoughts for the individuals and families affected by the senseless act of violence."
"We all know the familiar faces of our local UPS drivers and delivery persons," Lee said. "Today's tragedy will be felt in every community served by these committed employees.
KTVU reporter Tara Moriarty and Bay City News contributed to this report.