CHICAGO (CBS) — There was a large police presence at the 875 North Michigan building commonly known as the Hancock Building Friday night at 10 p.m. after a resident on the 57th floor reported hearing shots fired.

Police responded to the unit where they believed the shots came from, but no one opened the door.

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SWAT teams were then called in around 8:15 p.m.

A bullet fragment was found in one of the adjoining apartments, according to the Chicago Police Department.

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In an email, the building’s property management said police waited to enter the unit until they could obtain a search warrant, which took four hours to obtain.

Police said the SWAT team entered the apartment, but the shooter was no longer on scene. Property management said police and security reviewed camera footage and saw the person who allegedly fired the gun leaving the building through the loading dock shortly after the gun was discharged.

There were no reports of injuries, and the incident concluded shortly before 2 a.m., police said.

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