Kericho Deputy Criminal Investigation Officer (DCIO) Charles Mugambi was shot dead on Wednesday night.
The officer was shot at Pala, border of Kericho and Kisumu counties.
Residents of Kipsitet who heard gunshots reported to the police. Two officers who were with the deceased were arrested. They will help the police in investigations.
The police said the car believed to have been used by the deceased had six bullet holes and driver's seat was stained with blood indicating that the deceased was the one driving when the shooting occurred.
Mugambi was transferred to Kericho three months ago and it is believed that he was traveling from Kisumu to Kericho when he met his death.
The police said the weapon suspected to have been used to commit the murder was recovered and will be handed over to ballistic experts for analysis.