Iowa City police are looking for a 17-year-old suspect after a shooting early Sunday in the nightlife district near the University of Iowa campus, authorities said Wednesday, describing the incident as an escalation that followed a fight. Iowa City Police Chief Dustin Liston said officers responded to the fight call and arrived within 45 seconds.

Liston said reports indicate as many as 40 people may have been involved in the fight, and that after walking away from other participants, the suspect allegedly fired six times into a crowded pedestrian area on Iowa City’s downtown pedestrian mall. The mall is lined with shops, bars and restaurants.

Authorities said the 17-year-old, from Cedar Rapids, Iowa, will face attempted murder charges. Johnson County attorney Rachel Zimmermann Smith said an arrest warrant was issued for the suspect’s alleged role in the fight and that Iowa law requires the minor to be charged as an adult for forcible-felony offenses when the person is 16 or older.

Liston said five people were treated for gunshot wounds. He said three were University of Iowa students, and that one woman remained in critical condition Wednesday after sustaining a life-threatening injury to her head.

In addition to the head injury, Liston provided details about other victims’ injuries, saying one person was struck in the arm and chest, two were struck in one or both legs, and one was struck in the side of their stomach. He said one person remained hospitalized in stable condition, and that three victims had been released.

Police Chief Liston said the investigation is ongoing and that additional charges are expected. He said officers executed about three dozen search warrants as part of that work.

Liston also said the five victims were not “targets of the shooting,” adding that police had “no reason to believe they were otherwise affiliated with the fight that preceded the shooting.” He said police would continue to work to hold those responsible fully accountable and encouraged anyone with information about the incident or the suspect to come forward.