A gunman opened fire inside the Manhattan skyscraper that is the headquarters of private-equity firm Blackstone and the NFL, killing four people, including a police officer, before fatally shooting himself on Monday evening, authorities said. Another person was in critical condition, and others suffered less serious injuries.

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.

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.