A hit-and-run captured on video during Denver’s first evening of protests over police misconduct remains under investigation, though the city’s police department has made “significant progress,” Police Chief Paul Pazen said in an interview.

As protesters blocked traffic at Colfax Avenue and Broadway on May 28, a person behind the wheel of a black SUV appeared to drive through a crowd. A viral video of the incident showed one man climbing onto the car’s hood before dismounting. The driver then turned the car into the protester, striking him before fleeing south on Broadway.

Despite the visual evidence, Chief Pazen declined to say if police have a suspect or whether they’ve made an arrest.

“I can tell you that significant progress has been made on that case, lots of evidence, but for me to get into details on an open and active investigation, (that) could jeopardize the outcomes of cases,” Pazen said. “I can tell you that our investigators are working very hard on that case. There is significant progress that has been made.”

Pazen said that his department is “seeking justice for people and if we get ahead of ourselves, we can jeopardize the integrity of a case, which could create harm, and that’s the only reason that this has taken as long as it has.”

A separate hit-and-run two nights later resulted in injuries to three police officers and one bystander. Police arrested a suspect the next day.