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 killed four people in a midtown Manhattan office building left a suicide note indicating that he was targeting the NFL, police said.

In the aftermath of New York’s deadliest mass shooting since 2000, authorities are investigating the motives and background of the man who opened fire in a midtown Manhattan office skyscraper, killing four people and then himself.