Officer Gary Michael, who had been serving in the police force for less than one year, pulled over suspect Ian McCarthy for a vehicle registration violation around 10:45 p.m. on August 6.
Police said that after shooting Michael, the suspect fled in his vehicle, then crashed a few blocks away.
Surveillance video from two convenience stores in Clinton was used to link Mr. McCarthy and the abandoned vehicle, Sergeant Martin said.
Police consider McCarthy armed and unsafe. Authorities did not know whether he was wounded.
The Missouri State Highway Patrol says they are looking for Ian McCarthy, 39, of Clinton, in connection to the shooting.
"[Mr Michael] was heroic right to the end".
Authorities have identified a person of interest in the fatal shooting of a Missouri police officer. The officer was able to return fire, but police aren't sure if the suspect was struck.
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KSHB reports that police blocked off the area of the crash and set up checkpoints around Clinton as they continued to search for the suspect. He is wanted for questioning in the death late Sunday of 37-year-old Clinton police officer Gary Michael.
McCarthy now faces charges for first-degree murder and felony armed criminal action in Henry County, where the city of Clinton is located.
Michael returned fire, and the suspect drove off before crashing blocks away.
Michael was a lifelong resident of Clinton and leaves behind a wife and stepsons.
Missouri Highway Patrol Sgt. Bill Lowe called the incident "devastating" for the family and the close-knit police department.
No further details have been released.