Kentucky State Police said Thursday night at a news conference that 38-year-old off-duty Hopkinsville officer Phillip Meacham was shot that afternoon and was taken to a hospital, where he died. Meacham was married and had two "school-age" children.
The off-duty officer was in his personal vehicle when he was pulled over by the suspect, who police identified as 35-year-old James Kennith Decoursey.
Police were looking for Decoursey, who they said fled on foot and then stole a 1997 white Chevrolet pickup with license plate 2070GH.
Police said Decoursey should be considered armed and dangerous. They ask that anyone who sees him or that white pickup call 911 immediately.
State Trooper Rob Austin said law officers know Decoursey stole the white truck but it is possible he may no longer be in that vehicle. He would not elaborate on Decoursey possibly impersonating a law officer, citing the sensitive nature of the ongoing investigation.
Hopkinsville Police Chief Clayton Sumner said he spoke briefly to Meacham's wife, telling her "we'll find him," and offering condolences.
Sumner said his department is familiar with Decoursey, who has had previous arrests.
Gov. Matt Bevin also announced the death on Twitter.
In Frankfort, lawmakers in the House stood for a moment of silence after Rep. Walker Wood Thomas of Hopkinsville announced that an officer had been shot.
Hopkinsville is about 73 miles northwest of Nashville, Tennessee.
The Associated Press contributed to this report.