By Steven Graves

CHICAGO (CBS) — Police are searching for the person who shot and killed a woman and a teenager at a liquor store in Humboldt Park late Friday night.

As detectives investigate, there is a lot of evidence to work with, including surveillance video from the store at 501 N. Kedzie Av.

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Around 10:30 p.m. Friday, a 23-year-old woman and an 18-year-old man got into an argument with two other men in the store.

Things turned physical, and one of the men reached for a gun and shot the woman in the torso.

Workers at the store said the gunman also shot the 18-year-old as he stood in the doorway.

That’s when everything spilled into the parking lot, where the woman collapsed on the pavement and the teen ran off.

Store clerk Wesam Qoron said he has no idea what they were fighting about.

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“We don’t know anything about it. This was the first time they’ve come in here, because the customers we get, we know all of the customers. These people, they came in yesterday, it’s the first time they came in,” Qoron said.

The woman was taken to Stroger Hospital, where she was pronounced dead. The 18-year-old who was with her was taken to Humboldt Park Health, where he was pronounced dead.

The Cook County Medical examiner’s office has identified the woman as 23-year-old Destiny Nunez and the young man as Adrian Navarro.

Nunez’s family dropped off balloons at the store in her honor.

Police have not provided a description of the shooter.

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Workers said people have to wear masks in the store, so it was tough to make out faces.