San Francisco -- Eight men were arrested Tuesday in the 1971 killing of a San Francisco police officer that authorities say was part of a black power group's five-year effort to attack and kill law enforcement officers in San Francisco and New York. Police said all eight are believed to be former members of the Black Liberation Army, a violent offshoot of the Black Panther Party. The Aug. 29, 1971 shooting death of Sgt. John V. Young, 51, at a San Francisco police station was one in a series of attacks by BLA members on law enforcement officials on both...