MOSCOW, Idaho (AP) — Police say the killer or killers who stabbed four University of Idaho students to death remains at large, and the violence has prompted many students to leave town. The Moscow Police Department said Tuesday that the attack was targeted and maintained there is no imminent risk to the community. But so many students have left campus that university officials said a candlelight vigil originally scheduled for Wednesday would instead be held after the Thanksgiving break. Police say a knife or sharp weapon was used in the attack on the students. Autopsies expected to be completed later this week could provide more information about how the victims were killed.