TORONTO — Three pro-Palestinian activists were charged with assault stemming from a rally for Gaza in Calgary that turned violent.

Hundreds of pro-Palestinian activists had converged July 18 outside City Hall in the western Canada city when a small group of pro-Israel demonstrators gathered across the street. A series of scuffles broke out and three people were assaulted.

On Tuesday, Aziz Mohammad Madi, 18, was charged with two counts of assault, according to Sunmedia. In addition, Arlsan Khan, 27, and a 16-year-old — who cannot be named under Canadian law — are each facing one count. All three are scheduled to appear in court on September 15.

It took police nearly a month to press charges because of the complexity of the investigation, Inspector Cliff O’Brien told Sunmedia.

“One of the challenges with an investigation like this is you have several hundred people who are very passionate and emotional,” he said. “And there are thousands of images out there, including video.”

Charges are also expected against a fourth man, who has been identified by the police, but not yet found.