Police sent out a note to the media this evening:

On November 29, 2016 at approximately 7:55 PM, San Francisco Police received a 911 call about a person inside the Metreon Theater (4th/Mission Streets) possibly armed with a handgun. Officers from multiple districts responded to the area, ordering the evacuation of the theater in an abundance of caution. One subject was located and detained, with a handgun also located at the scene. The investigation is still underway and the area should be avoided until further notice. No injuries to any involved parties.