"Compared to what's on the news, I don't think any one of us, none of my teammates, sensed anything like this from Shane," the former teammate told The Post.

Investigators found the note in the wallet of 27-year-old shooter Shane Tamura who police said opened fire inside of 345 Park Avenue.

The guard had been fatally shot as he crouched behind a desk to take cover as the gunman sprayed the building’s lobby with bullets, police said.

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.

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

The assault rifle used in mass shooter Shane Tamura’s deadly rampage at a NYC skyscraper was assembled piece by piece – with the critical part purchased by his boss, according to officials and

The father of hero NYPD cop Didarul Islam grew so distraught when he learned of his son’s death at the hands of a deranged gunman in Midtown Manhattan that he suffered a stroke, his family told The Post.