Shane Tamura, 27, who fatally shot four people in the building that houses the National Football League's headquarters Monday, said in a suicide note that he had chronic traumatic encephalopathy, known at CTE,

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

Police are retracing Tamura's movements from Nevada to New York after a Midtown Manhattan shooting that left four people dead and another wounded