Hand signals captured on videotape are once again being scrutinized around the NFL. Only this time, it's not the New England Patriots studying them for a competitive advantage, but league officials in search of a more sinister message. The NFL, concerned that some players might celebrate by flashing the hand signals of street gangs, has hired experts to examine game tapes and identify the gestures. "There have been some suspected things we've seen," said Milt Ahlerich, the league's vice president of security. "When we see it, we quietly jump on it immediately, directly with the team and the player or...