Once a promising athlete, the 27-year-old faded from public view—until he showed up at 345 Park Avenue, gun in hand.

The gunman suspected of targeting the National Football League headquarters in New York, killing four, was a former football player at two Southern California high schools.

Shane Tamura, 27, is the suspect alleged to have shot and killed four victims while wounding an NFL employee. Tamura then fatally wounded himself. Further investigation into the shooting revealed that Tamura was targeting the NFL's offices, but "appeared to have gone to the wrong floor" in the 44-story skyscraper.