(Portland, OR)  --  Federal charges are being filed against 74 people involved in Portland demonstrations.  U.S. Attorney Billy J. Williams announced the charges yesterday, claiming violent agitators have hijacked the protests.  Some of the charges, including felony assault of a federal officer, could carry sentences up to 20 years in prison.  Not all of the cases involve federal property.  Federal prosecutors say they're reviewing acts of destruction committed throughout the city.