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,

New York City police detectives searched a studio apartment in Las Vegas that belonged to the suspected gunman in Monday's mass shooting at a Midtown Manhattan.

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