Follow along for live updates on the New York City shooting, where police investigate motive after five people, including the gunman, were killed in the Monday shooting.

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.

A New York City police officer who was among the four people shot and killed by a gunman during a rampage at a Manhattan office tower will be laid to rest Thursday. Officer Didarul Islam, 36, was fatally shot Monday in a midtown building housing the National Football League’s headquarters.

One person is dead and at least 22 people have become sick from a Legionnaires’ disease cluster in New York City since last Friday, health officials said.

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.