The man who killed four people in the New York City skyscraper that is home to NFL headquarters carried a note blaming the league for his mental health problems.

The Manhattan high-rise shooter, a former high school football player, left a note referencing the brain disease CTE and appeared to have targeted the NFL’s offices, authorities said.

The man who shot and killed four people in Manhattan had legally purchased a firearm in Nevada, where he lived, despite a record of mental health problems.