1 dead, 3 injured in shooting at rapper T.I.'s concert at Irving Plaza in Union Square

UNION SQUARE, Manhattan (WABC) -- Four people were shot at a T.I. concert at Irving Plaza on Wednesday night. One man died from his injuries.

It happened at 10:15 p.m. at the 1,025-person ballroom-style music venue. It's not yet known how many people were inside.

T.I. the rapper was about to take the stage at the time of the shooting but was not yet performing.

Witnesses report hearing an argument in the balcony area and then at least two gunshots.

Two men in their 30's were shot. One man died, the other remains in critical condition.

A 26-year-old woman was shot in the leg and is in serious but stable condition.

A fourth person walked into NYU medical center with a gunshot wound. Their condition is not yet known.

Detectives are looking at video in the area and are interviewing witnesses to help identify a suspect or suspects.

There was security and metal detectors were used at the venue. Police say proper protocol was followed.

Ballistic evidence was recovered at the scene.