A Butler man will stand trial on charges he attacked and bloodied a city police officer last month.

Zachary R. Baer, 20, on Monday waived his preliminary hearing in Butler on a felony count of assault.

Baer is accused of punching Patrolman Caleb Forsythe in the face Dec. 29 after police responded to a call on Center Avenue.

While Forsythe spoke to Baer, who was reportedly having “mental health issues,” the defendant suddenly hit the officer, according to court documents.

Before the assault, Baer showed no sign of aggression.

Forsythe suffered swollen and bloody lips. He did not miss any work.

Baer was immediately arrested. He was arraigned on a charge of aggravated assault and placed in the Butler County Prison on $50,000 bail.

In exchange for Baer waiving his case to court, District Judge Pete Shaffer on Monday reduced his bail to $20,000.

Baer, who remained in jailed this morning, will be formally arraigned in county court on Feb. 18.