Jimmy Lam was an American resident of San Francisco, California. He was an employee of a UPS facility in the city.

Lam had a history of mental illness. He was also estranged from his wife.

On June 14, 2017, just before 8:55 a.m., Lam opened fire at the warehouse he was employed at in San Francisco, fatally shooting three people before killing himself.

One of the victims was identified as Mike Lefiti, a coworker and married father of five.

Lam was armed with a MAC 10 when he committed the mass shooting. Officers found wounded victims inside the building and brought them out to safety. When officers located Lam, he put the weapon to his head and shot himself in an act of suicide.

He had filed excessive overtime grievance with the company before the incident.

A retired co-worker who worked with him for more than a decade described him as a loner.