Utah investigators sought help from the public on Wednesday as they work to unravel who was at fault when a safety volunteer at a weekend “No Kings” rally fired at an alleged gunman and inadvertently hit and killed a protester.

The alleged rifleman, Arturo Gamboa, 24, was also shot and was taken into custody on a murder charge, Salt Lake City Police Chief Brian Redd said at a Sunday news conference. The bystander who was killed was identified as Arthur Folasa Ah Loo, 39, a fashion designer from Samoa.

A person shot and killed an innocent bystander during a “No Kings” protest in Salt Lake City, Utah on Saturday.