Surveillance video shows Darrin Campbell—the Florida dad accused of killing his family and himself and setting their house on fire—buying fireworks in a store three days before the tragedy, ABC Action News reports. Campbell was "calm ... like any other customer," said a salesperson who cashed out the $600 purchase. Campbell said he was doing "early Fourth of July shopping" and wanted to use a half-off coupon, the salesperson said. "This is nothing to be alarmed about as far as a customer making a purchase." (The Tampa Bay Times has the video.) In other developments: