Shane Tamura, the 27-year-old man who shot and killed four people inside a Midtown office building, didn’t show up for his shift as a Las Vegas casino security guard on Sunday, according to authorities.

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

Wearing body armor and wielding an assault-style rifle, the alleged gunman burst into a Midtown Manhattan office building shooting victims at random.