Investigators are examining why the gunman who killed four people before taking his own life at a New York City office tower targeted the National Football League and whether he suffered from a brain disease.

Zohran Mamdani spent the last hours of his wedding celebration in Uganda huddled remotely with his team after learning of New York’s deadliest mass shooting of the last 25 years.

The killing of four people including a police officer in a Midtown Manhattan office building rattled a city where mass attacks are rare and violent crime has declined.

New York City officials said they are investigating a cluster of Legionnaires' disease that has caused one death and nearly two dozen illnesses.

At least 22 people have fallen ill, including one person who has died, from Legionnaires’ disease in New York City over the last two weeks, according to the city’s health department. City health officials believe that the people most likely became ill after breathing in bacteria sprayed from a cooling tower in central Harlem.