Park City police shut down rapper Wiz Khalifa’s concert this weekend after an officer patrolling the event found “multiple code violations” and was injured while trying to address them.

The crowded event at Park City Live got rowdy after midnight Saturday, said police Capt. Phil Kirk. Several officers were there to conduct compliance checks at the Main Street venue and warned staff there to fix the issues.

Kirk wouldn’t detail what the problems were, but said that nothing was done to address them and police decided to close the concert at 12:30 a.m.

During that effort, an officer was hit in the head after someone in the crowd threw something. It’s not clear what the object was, but the officer did have a small cut.

In a statement, Kirk said: “The incident remains under investigation and no additional details will be released at this time.”

Khalifa, whose real name is Cameron Jibril Thomaz, is known for the hit songs “Say Yeah” and “Black and Yellow." He responded to the police with two tweets Saturday morning.

The first said, “Homie wit tha badge can succ it easy. He ruined it for everybody.”

In the second, Khalifa said he “had to run from the cops last night. Good thing I remembered my training.”

General admission tickets to the show cost $99. VIP spots went up to $200.

The concert coincided with the Sundance Film Festival, also happening in Park City this week.