ADAMS, Mass.—The flag-draped casket of U.S. Capitol Police Officer William Evans was carried into a Massachusetts church on Thursday by his fellow Capitol officers as dozens of state police troopers stood in the street in a steady downpour and saluted. Evans was killed this month when a driver struck him and another officer at a barricade outside the U.S. Senate in Washington. The private funeral Mass at St. Stanislaus Kostka Church in Adams was followed early Thursday afternoon by a procession to Bellevue Cemetery—where Evans was to be laid to rest beside his father, Howard. Hundreds of police officers from department across the region lined up outside the church before the Mass under a U.S. flag held aloft by an Adams Fire Department ladder truck. Several residents stood under umbrellas nearby and gathered on the streets for the funeral procession to the cemetery to say goodbye to the officer whose …