FRESNO, Calif. (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. Within minutes, the alleged gunman in the deadly rampage was under arrest.

Fresno Police Chief Jerry Dyer credited the technology Wednesday with the swift capture of Kori Ali Muhammad, a 39-year-old black man who authorities say killed three people Tuesday in a bid to wipe out as many whites as possible.

"He was in custody within 4 minutes and 13 seconds," Dyer said Wednesday at a news conference where he played audio...