Victims of San Francisco UPS shooting appear to have been targeted, police say

— -- The three people who were shot and killed at a San Francisco UPS facility last week appeared to have been targeted, police announced Friday.

The shooter, identified by police as 38-year-old UPS employee Jimmy Lam, said nothing and gave no warning before he began firing, according to the San Francisco Police Department. Witness statements and video surveillance of the incident show Lam passing other people to get to his victims, indicating that the victims were targeted, police said.

"We also know from looking at video that there were times where Mr. Lam passed employees without ... there being any interaction, and that would lead us to believe that these specific individuals were targeted," SFPD Cmdr. Greg McEachern said.

The shootings of the victims were not captured on any kind of video, police said.

Lam was carrying two guns at the time of the June 14 incident, but he only used one of the weapons, which San Francisco police described as an "assault-type" pistol with an extended magazine.

Both guns were apparently stolen -- one from nearby Napa and the other from Utah, according to the San Francisco Police Department. Lam also had a bag with one box of ammunition, police said.

After firing inside the facility building, police said Lam calmly walked outside the building and fired multiple rounds at another victim, killing him. He then walked back inside the building as police arrived and shot himself in the head as he was confronted by officers.

"The officers observed that Mr. Lam was armed with a firearm and he had it pointed at his head," McEachern said. "The officers instructed Mr. Lam to put the gun down in an attempt to take him into custody but Mr. Lam shot himself."

A total of 20 rounds were fired throughout the ordeal, police said.

Investigators are reviewing a journal and computer found at Lam's home, but a motive for the shooting has still not been established, police said.

Lam had filed a grievance in March complaining that he was working excessive overtime, The Associated Press reported last week.

The facility is an area package sorting hub and package delivery center, UPS said last week.