More than a decade before he turned a Midtown NYC office building into a killing ground, Shane Tamura stood out as a rising star on a high school gridiron. Police believe the 27-year-old shooter’s obsession with CTE,

Police have identified the man who they say entered a Midtown Manhattan office building wearing body armor and opened fire, killing four people with a high-powered rifle, as Shane Devon Tamura.

The gunman, who said in a note he believed he had CTE, targeted skyscraper that houses the NFL's headquarters.