A note found in the gunman's wallet was critical of the NFL and mentioned CTE. The 27-year-old wrote, “Study my brain please. I’m sorry."

The Rudin family, which owns the building and Rudin Management, said in a statement that one of their employees was a victim of the shootings but did not disclose the person’s name at the request of relatives. Police officials said a woman was found dead on the building’s 33rd floor in Rudin’s offices.

A gunman opened fire inside a building in New York City on Monday evening, killing four people and injuring a fifth.