TWINSBURG, Ohio -- A 23-year-old man accused of fatally shooting a Twinsburg police officer pleaded not guilty on Monday.

Ashford Thompson appeared for a video arraignment, and bond was set at $5 million.

Thompson is accused of shooting 33-year-old Officer Joshua Miktarian early Sunday morning after the officer pulled him over on Glenwood Drive at Route 91.

Thompson's defense claims the suspect shot in self-defense, and said they have a witness that will back up that claim.

Miktarian stopped Thompson because he heard loud music coming from the car and thought Thompson may have been under the influence, officers said.

A preliminary autopsy showed that Miktarian was shot four times in the head. Because only one bullet was found, investigators are taking another look at the crime scene and could collect more evidence there.

After an extensive manhunt, Thompson was arrested by Bedford Heights police. A weapon was recovered upon his arrest. He had a concealed weapon permit.

Thompson's only prior offense was having illegally tinted car windows.