The suspect, Vance Boelter, was appointed more than once to the Workforce Development Board, where he served with State Senator John A. Hoffman, who was shot on Saturday.

The general overseeing the military response to the Los Angeles protests said about 200 Marines had been deployed to the Wilshire Federal Building

Organizers have planned demonstrations in cities and towns across the country on the same day as President Trump’s parade in Washington to celebrate the Army.

Police have arrested more than 1,000 people in the past week as civil unrest that began after immigration sweeps in Los Angeles spread to cities across the country.