CHICAGO (CBS) — Three people were shot early Monday in the Hyde Park neighborhood, near the University of Chicago campus.

University police issued a campus security alert at about 2 a.m., after three people were shot in an alley in the 5400 block of South Ellis Avenue.

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Police said two men and a woman were sitting in a blue Ford Thunderbird in a parking lot, when someone came up to the car and opened fire around 12:30 a.m.

Sources said, after they were shot, the victims ran to a University of Chicago parking garage at 55th Street and Ellis Avenue, and called for help.

The 22-year-old woman was shot in the chest and stomach. She was listed in serious condition at John H. Stroger Jr. Hospital of Cook County.

A 35-year-old man was shot in the leg, and also was taken to Stroger Hospital, for non-life-threatening injuries.

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The third victim, a 24-year-old man, was shot in the chin, chest, and leg. He was taken to Northwestern Memorial Hospital in serious condition.

Police said investigators do not know yet what led up to the shooting, but at least 16 shots were fired. The victims’ car was riddled with bullets.

“I didn’t know they were shots. I heard crashes. I thought they were, like, it was like metal on metal was what I thought it was, because we don’t hear a lot of gunshots here,” Hyde Park resident Katrin Asbury said.

The victims were not affiliated with the university, but sources said the two men have gang ties.

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No one was in custody Monday morning.