A demonstrator who was shot on Saturday during Salt Lake City’s “No Kings” protest has died, Utah police said on Sunday afternoon.

The man, Arthur Folasa Ah Loo, 39, had apparently been shot by a man who had been part of the event’s peacekeeping team.

“Our victim was not the intended target,” Brian Redd, the Salt Lake City police chief, said, “but rather an innocent bystander participating in the demonstration.”

Arturo Gamboa, 24, was taken into police custody on Saturday evening on a murder charge, said Redd at a Sunday news conference. Ah Loo, who had been taken to the hospital on Saturday evening, where he died from his wounds.

Redd said a man in a brightly colored vest fired three shots from a handgun at Gamboa, inflicting a relatively minor injury to Gamboa but fatally shooting Ah Loo.

Two of the peacekeepers in neon vests allegedly saw Gamboa separate from the crowd of marchers in downtown Salt Lake City, move behind a wall and retrieve a rifle around 8pm, Redd said.

When the two men in vests confronted Gamboa with their handguns drawn, witnesses said Gamboa raised his rifle into a firing position and ran toward the crowd, said Redd.

That’s when one of the men in the bright vests shot three rounds, hitting Gamboa and Ah Loo, said Redd. Gamboa, who police said didn’t have a criminal history, was wounded and treated before being booked into jail.