"It was heartbreaking, shock, still in disbelief," said Walter Roby, the former assistant football coach at Granada Hills High School in Los Angeles.

The man who fatally shot four people at a New York City office tower Monday, including an off-duty police officer, and wounded a fifth before taking his own life, was a standout high school football player in Southern California before becoming a Las Vegas resident.

The gunman in New York City who shot and killed four people, including a police officer before taking his own life on Monday attended two Southern California high schools where he played football, KTLA has confirmed.