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.

Police say a gunman who killed four people in a Manhattan skyscraper before taking his own life claimed to have a brain disease linked to contact sports and was trying to target the National Football

Shane Tamura said he had CTE. His claim, which is unproven, has again put a spotlight on the NFL's troubling history with its players and the disease.

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, and was targeting the NFL — but took the wrong elevator, officials said Tuesday.

While news of the shooting sent shockwaves across the league, the development that the NFL offices were specifically targeted left some deeply stunned.

We have reason to believe he was focused on the NFL agency that was located in the building,” New York City Mayor Eric Adams said during an interview on MSNBC Tuesday.

At least two reported shot after gunman entered New York Midtown building where Blackstone and NFL based - Large numbers of police seen outside Manhattan skyscraper

The ordeal in the Blackstone Building in Midtown Manhattan in New York City has led to a complete lockdown - as authorities have warned people to remain vigilant