(Portland, OR)  --  A federal investigation is underway into the serious injury of a protester who was shot in the head by a federal police projectile during demonstrations in downtown Portland.  Mayor Ted Wheeler says the U.S. Marshals Service will be conducting a full investigation into the incident Saturday night.  The Portland Police Bureau says protesters were gathered around the Mark O. Hatfield U.S. Courthouse when federal officers released tear gas and other crowd control munitions on them.  Protesters Donovan LaBella was hospitalized in critical condition after a police projectile struck him in the head.