VISTA — Law enforcement officers from across North County raced to a Vista Target on Tuesday night after several 911 callers reported hearing what sounded like gunshots in the store but turned out to be fireworks, authorities said. The callers believed there was an active shooter in the store, as did sheriff’s deputies when they first went inside, but they later discovered the exploded firecrackers inside a small trash can. Now, detectives are seeking the public’s help to identify the person thought to be responsible for causing the scare. Sheriff’s officials say surveillance footage showed this man appearing to set off firecrackers Tuesday night inside a Vista Target, prompting an active-shooter scare.