MIAMI — In the span of just over a decade, Key Biscayne police received a series of complaints about a gymnastic coach’s allegedly abusive behavior with young girls, police reports and interviews with the Miami Herald reveal. The coach’s name: Oscar Nicolas Olea. He is 38. He has not been charged with any crimes and continues to teach gymnastics to girls, teenage and younger. He and his lawyer deny he has done anything wrong and several parents reached out to Herald reporters to offer their praise for the coach. But a Herald investigation has uncovered at least five alleged victims, all of who…