Around 10:30 p.m., officials say they received calls of a man wearing camouflage pants, a black bulletproof vest, and carrying an assault-style rifle.
Once they arrived, officers say they saw the suspect walking in front of 100 Boyd Road and issued a lockdown order. They sealed off an area between Contra Costa Boulevard, Cleveland Road, Crescent Plaza and Hookston Road.
During this time, all residents were told to stay inside and lock their windows and doors.
In a statement, Lt. Dave Nichols says the Central County Regional SWAT team was activated and completed an exhaustive search of the apartment complex at 100 Boyd Road and the surrounding areas. The subject was not located and his identity is currently unknown.
He is described as a white male adult, approximately 5 feet 6 inches with brown hair and a light beard. Police say he was wearing a dark beanie cap, camouflage pants and a black ballistic vest.
The Pleasant Hill Department is continuing to investigate this incident to determine the identity of this subject. Anybody with information regarding this investigation is requested to call the Pleasant Hill Police Department at (925) 288-4630.