(KRON) — San Francisco Police investigators are providing new information more than a week after the mass shooting at the UPS facility. SFPD has interviewed more than 100 witnesses and recovered video from the UPS facility.

But the shooting was not captured on camera.

Last week Jimmy Lam fired 20 rounds from a semi-automatic pistol killing three fellow workers at the San Francisco warehouse before taking his own life.

At 8:50 am last Wednesday there was a daily meeting in the UPS facility that was attended by the gunman and the victims, police say during that meeting and without warning Lam opened fire, shooting 4 people in the meeting, 2 of those died.

Lam then walked outside the building, he shot another victim multiple times. At that time Lam walked back into the UPS building, when officers arrived they confronted him, that is when Lam took his own life.

Police say the three victims that died appeared to be targeted.

Lam was armed with multiple guns and one box of ammunition. The weapon used in the shooting, which is an assault type pistol, was stolen from a person in Utah.

He was armed with two stolen guns total and appeared to target his victims. Lam also had a semi-automatic handgun stolen from Napa County, California.

Commander Greg McEachern said it was not known who stole the weapons.

Investigators said Friday that they are not sure of a motive for the shooting. However shortly after the shooting

A San Francisco Police Department official has said Lam appears to have felt disrespected by co-workers but did not know if that motivated the shooting that left Lam dead and another driver with a gunshot wound. The officer spoke on condition of anonymity because the officer was not authorized to speak publicly about the investigation.

But the three drivers who were killed last Wednesday were known as kind and helpful among co-workers and clients, wounded driver Alvin Chen told The Associated Press in an interview. It would have been out of character for them to single anyone out for disrespect, he added.WHAT OTHERS ARE CLICKING ON:

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