A senior police officer was on Saturday night shot dead by his junior at their camp in Maralal.
Samburu County police commander Karanja Muiruri said the motive of the killing was not immediately established.
Mr Muiruri said the junior officer stormed the police camp and opened fire on his boss killing him instantly. He said the suspect was arrested and disarmed.
He added that the suspect will be arraigned once police complete investigation.
A police officer based at the station, who sought anonymity because he is authorised to speak to the press, told the Nation that the suspect was enraged after he was transferred from a construction site that he had been manning.
The body of the victim was taken to Samburu County Referral Hospital Mortuary.