Harrison, 28, has been charged with 12 separate counts, including manufacture/delivery of a controlled substance, delivery of Schedule I or II narcotics, fleeing/eluding an officer resulting in death, bail jumping, and knowingly operating a motor vehicle while revoked.
Police had been investigating Harrison at least since late last year, when he was connected to a fentanyl overdose death in Waukesha County. Undercover officers staged drug buys with the suspect on multiple occasions.
On the day of Irvine's death, Harrison was driving eastbound on W. Silver Spring in front of the officer's squad car. According to the complaint, Officers Irvine and Matthew Schulze ran Harrison's license plate, and attempted to perform a traffic stop when the light they were at turned green.
Harrison sped off at that point, driving as fast as 96 miles per hour. He later told investigators he was afraid of getting pulled over because he had a gun in the car and was driving on a revoked license, the criminal complaint says.
Harrison was arrested by officers later in the day after fleeing yet again when undercover officers attempted to arrest him. According to the complaint, the suspect had been released on bond for a previous operating while revoked offense at the time of the crash.
He faces more than 120 years in prison if convicted of all charges.