(AP) — Acoustic sensors mounted on lampposts and telephone poles picked up the crack of gunfire and rapidly enabled police to zero in on where it was coming from. Police say Muhammad randomly targeted white men he encountered in a tree-lined Fresno neighborhood, firing 17 rounds within a few minutes before running out of ammunition, police said. Computers and technicians at a California-based center distinguish the sound of gunfire from other noises and triangulate the shots, in much the same way that cell towers are used to zero in on the location of a cellphone. A one-year contract with ShotSpotter costs $55,000 to $95,000 for each square mile. Because of the cost, cities often limit the technology to high-crime areas.