Tamura was involuntarily held after being considered a danger to himself or others, according to a law-enforcement official.

P olice 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 Palmetto State Armory AR-15 assault rifle used in the shooting that killed an NYPD cop and four civilians is .223-caliber and is equipped with a black scope, a handguard and a shoulder sling.

Shane Tamura, the Park Ave. gunman who killed an NYPD officer and three others before taking his own life, left behind a suicide note saying he suffered from CTE, a brain injury often linked to playing football, police sources said Tuesday.

Nevada's gun laws are again under scrutiny after a Las Vegas man opened fire in Midtown Manhattan, killing four people and injuring another.

Suspected gunman Shane Tamura had a ‘documented mental health history’ and ‘sprayed’ the Manhattan office building lobby with a military-style assault rifle, police say

No motive has been announced. A suicide note was found expressing grievances with the NFL and saying Tamura suffered from CTE, a source said. Follow for live updates.

Shane Tamura, who shot and killed four people in a Manhattan office building, once worked surveillance for a Las Vegas casino. In a suicide note, the 27-year-old referenced CTE and claimed the NFL "failed" him.