NFL Commissioner Roger Goodell has reacted with great sadness to the deadly attack in New York, which apparently targeted the office of the professional football league. The act of the 27-year-old man from Las Vegas, who shot four people in an office building and then himself, was “an unspeakable act of violence,” Goodell told US broadcaster CBS.

In a statement, Goodell also said that an NFL office employee had been seriously injured but was now in stable condition in hospital. All other employees on site were reported to be unharmed. A 36-year-old police officer, a manager at the investment firm Blackstone, and two other men were killed in the shooting.

“We are deeply grateful to the police officers who responded quickly and decisively to this threat, and to Officer Islam, who gave his life to protect others,” Goodell said. The commissioner assured his employees of “significant support” and said there would be “increased security presence” in the building “in the coming days and weeks.”

In a farewell note found on the dead attacker, according to New York Mayor Eric Adams, the shooter claimed to have chronic traumatic encephalopathy (CTE). This is a brain disorder caused by severe head injuries and can occur in contact sports. The perpetrator apparently acted out of hatred for the football league. “He seemed to blame the NFL for his injuries,” the mayor said.