The gunman suspected of targeting the National Football League headquarters In New York, killing four, was a former standout football player at two Southern California high schools.

Here's how NFL players, coaches and executives reacted to a mass shooting at the league's office building in Manhattan:

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

Four people were killed and a fifth was injured in a mass shooting at a Midtown Manhattan office building on Monday. Among those killed was an officer who was a dad of two with a third on the way. Didarul Islam, 36, was an off-duty New York City police officer assigned to a Bronx precinct, New York City Mayor Eric Adams said.

Multiple people were killed in a shooting Monday in a corporate office building in Midtown Manhattan, according to media reports. The New York Police Department posted on X that the scene “has been contained and the lone shooter is dead.”

Arriving officers found 11 people shot including a 27-year-old man pronounced dead at the scene, Schierbaum told reporters during a late-morning news conference. The other 10 victims included an 18-year-old man who was taken to a hospital in critical condition.

Shane Devon Tamura fatally shot four people, including an NYPD officer, in midtown Manhattan before killing himself, officials said.

Jackson County Circuit Judge Susan Jordan sentenced Kevin Jamall Johnson Wednesday, July 23, to two years on probation and a suspended sentence of 93 days in jail, court records show.

The 27-year-old man who shot and killed four people at a Midtown office building on Monday carried a note in his pocket, police sources told ABC News.