At least four people are dead in a shooting at a UPS warehouse and customer service center in San Francisco, after a gunman in a UPS uniform opened fire on employees, before turning the gun on himself. Local law enforcement are conducting an investigation, and "cannot provide the identity of the persons involved at this time. (UPS official statement) This happened at the UPS facility on 2222 17th Street, in the Potrero Hill neighborhood. For updates, please visit NBC Bay Area.