Chicago’s acting top cop told reporters Tuesday that police believe a mass shooting this weekend at a gathering in Washington Park was “somewhat targeted” and likely involved multiple shooters and an exchange of gunfire.As city officials announced the opening of a resource center for those imp acted by violence, interim police Supt. Fred Waller also alluded to the potential use of a “switch,” a small device that turns a semi-automatic pistol into a machine gun.“It happens in a matter of seconds. But we also know that there probably was some return fire also. So some people in the crowd [were] probably armed,” Waller said, standing alongside Mayor Brandon Johnson and other city leaders at the Washington Park Refectory.The shooting happened around 11:30 p.m. Saturday as former residents of the Robert Taylor Homes gathered for a reunion on the east edge of the park in the 5400 block of South Cottage Grove Avenue, according to police and a victim of the attack.Chicago Park District Supt. Carlos Ramirez-Rosa said police were “working to close the park and disperse individuals” when the gunfire erupted, roughly a half-hour after the park was supposed to close.Rontonio Guterz, 35, was killed and 14 others were wounded, officials have said. It marked Chicago’s largest mass shooting this year. A piece of police tape hangs on a Washington Park sign after a mass shooting late Saturday left a man dead and 14 other people wounded.Candace Dane Chambers/Sun-Times A police report obtained by the Sun-Times says that two gunmen wearing ski masks opened fire, and someone at the gathering shot back.At least 36 shell casings were found on Cottage Grove Avenue and inside the park, including casings from a rifle, according to the report. A weapon was also recovered.Waller told reporters that the amount of shell casings could indicate there was “more than just one offender.” He said investigators have obtained “some videos tracking vehicles” and were “canvassing the scene” for all types of footage, including from city POD cameras.Local Ald. Jeanette Taylor (20th) told reporters that she drove past the park around 8 p.m. and thought about reporting the cars she saw parked on the grass. But she said she knows the “effects of calling the police prematurely, so I didn’t call.”“They were just out there hanging, listening to music. They were eating. You saw kids out there, like it was a good time. My only beef was: get off the grass,” Taylor said. “ And so hindsight being 20/20. [But] people should be able to hang out at the park. That's not the issue. The issue is when you got some idiot who decides to go up and shoot in a crowd.”Mayor Johnson said the shooting was “absolutely unacceptable, and it does not reflect the true nature of who we are as Chicagoans.”“In the face of that pain, our responsibility is not simply to condemn what happened,” the mayor said. “It is to show up for the people who are harmed, surround this community with support, and then make sure that no one has to navigate the aftermath of this tragedy alone.”Mental health services, crisis support and help applying for victim compensation will be available at the field house from 4-7 p.m. Thursday.Waller said the department’s victim services team is canvassing the area Tuesday to spread word about the event, which is open to the public regardless of whether someone was involved in the most recent shooting. Related Chicago’s biggest mass shooting this year sees 1 killed, 14 hurt in Washington Park Man killed in Chicago’s largest mass shooting of 2026 was outgoing, ‘loved everybody,’ his sister says ...read more read less