A UPS employee opened fire in a San Francisco package delivery facility in a shooting spree that left four dead, including the gunman, on Wednesday, police and the company said. The gunman barged into the facility near 17th and Vermont streets around 9 a.m. local time and began shooting, San Francisco police confirmed to Fox News. The building is located in the Potrero Hill, which is about 2 1/2 miles from downtown San Francisco. Two other people remain hospitalized. The gunman died of a self-inflicted wound, police said. The motive of the shooting is still unclear, police said, adding that they believe the incident was not terror-related. The FBI was aware of the incident but did not intervened, the bureau told Fox News.