Greek authorities are ordering two policemen to stand trial for the fatal shooting of a teenager last year that touched off the country's worst riots in decades. A council of judges Friday extended the pretrial detention of the officers for another six months. No trial date was set. The two are charged with murder and attempted murder for the Dec. 6 shooting in central Athens, which followed an altercation between the officers and a group of youths. The charges carry a maximum life sentence. The policemen claim Alexandros Grigoropoulos, 15, was killed by a ricochet after they fired a warning shot in the air. The teenager's death sparked rage across Greece, with days of violent protests in which dozens were injured and more than 250 arrested.