A gunman shot and killed multiple people, including himself, in a New York City skyscraper on Park Avenue in Manhattan. The building was home to a number of offices including the headquarters of the National Football League.

Follow along for live updates on the New York City shooting, where police investigate motive after five people, including the gunman, were killed in the Monday shooting.

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 the cognitive problems he developed as a high school football player.

NYC gunman Shane Tamura is seen on video talking about his high school football career in California after a game in September 2015.

The National Football League Players' Association offered its condolences to those affected by the shooting at the building of the league's headquarters.

Baltimore Ravens head coach John Harbaugh commented on the shooting that killed four people inside a New York City building that houses the NFL headquarters.

Mayor Eric Adams said Tamura targeted the league's headquarters in New York, leaving a note claiming he had CTE. Tamura also wounded an NFL employee, as police said upon entering the building at 345 Park Avenue in midtown Manhattan,

Shane Tamura, a former football player at Golden Valley and Granada Hills high schools, entered a New York skyscraper and began spraying bullets, police say.

A man exited a double parked BMW with an M4 rifle and then walked toward the skyscraper that is home to the headquarters of both the NFL and Blackstone, one of the world’s largest investment firms, as well as other tenants on Monday evening, according to surveillance video.

A motive has been announced for the gunman who took four lives in a New York City shooting on Monday evening. A man, carrying a long rifle, went into a New York City skyscraper on Monday evening, shortly after 6 p.

An NYPD officer, a Blackstone executive, a Rudin Management associate and a security guard were killed in the shooting at Manhattan's 345 Park Avenue.