Shane Devon Tamura, the man identified as the gunman who killed four people in a deadly shooting at a midtown Manhattan office building that houses the NFL 's headquarters, was once a standout high school football player, praised by former teammates.

In a shocking display of violence on Monday evening, 27-year-old Shane Davon Tamura from Las Vegas unleashed chaos in a Manhattan high-rise, leaving four people dead—including an off-duty NYPD officer—and another critically injured.