Las Vegas police

Las Vegas police managed to arrest him immediately

Before he mowed down concertgoers from a perch high in a hotel tower, Stephen C. Paddock created a ring of surveillance around him, with video cameras in his suite and in the hallway, law enforcement officials said on Tuesday. But investigators were still at a loss to offer a motive for the massacre.

Las Vegas police have launched a homicide investigation into the death of B.B. King, a coroner's office said May 25, after the daughters of the blues guitar legend reportedly accused his aides of poisoning him.