Officials say a man carrying a rifle killed four people at a New York City office tower. The shooting took place Monday afternoon at a midtown Manhattan office building that houses finance companies and the NFL headquarters.

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.

There were 23 shell casings and 13 bullet fragments recovered from the lobby of 345 Park Avenue and 24 spent shell casings on the 33rd floor, police said.