As Michael exited his vehicle in downtown Clinton, the alleged shooter also got out of his auto and fired once at the officer before fleeing the scene and crashing his vehicle into an embankment about four blocks away, Lowe said.
The officer, Gary Michael, who was with the force less than a year, pulled over a suspicious vehicle around 10:45 p.m. on Sunday, according to Missouri State Highway Patrol Sgt. Bill Lowe.
Lowe could not specify how investigators came to find it.
McCarthy, 39, is charged with first-degree murder and armed criminal action in the death of Officer Michael.
Henry County prosecutors charge William Grant Noble, 35, of Clinton with having thrown the rifle police claim was used by McCarthy into a body of water knowing it had been used in a crime. When asked why he was behaving that way, he told police he had sold the gun to McCarthy.
Ian McCarthy was arrested and charged with killing Clinton Police officer, Gary Michael. Noble provided police a written statement about selling the firearm to McCarthy. They say there were three weapons upstairs and a gun safe downstairs. Noble then "stared" at the officer for about a minute, "blankly", before the officer asked again and he said that he knew where the weapon was.
His bond has been set at $25,000 cash only.
Lowe earlier said that a gun had been found in a creek about two miles north of Clinton.
McCarthy was taken to a Kansas City area hospital for treatment and then was taken into custody at the Henry County jail.
As the officers were getting ready to leave, one of them asked Noble if he knew where the gun was.
An officer walked to the edge of the water near NW 300th Road and NW 131st Road and spotted the stock of a weapon under water. A news release says others may be implicated in the case as the investigation continues. Before shots were fired, Michael managed to give a description of a dark SUV with Missouri plates, which is registered to McCarthy, according to a probable cause statement.
The Highway Patrol says Officer Michael had stopped a vehicle for a registration violation.