Bandits killed a police reservist in Karare, Marsabit County on Saturday when a driver of a lorry he was travelling in defied the gunmen's orders to stop, police say.
The driver of the lorry and another passenger escaped unhurt in the 1:30 am incident.
Marsabit acting Police Commander Mark Wanjala said the raiders flagged down the lorry that was travelling to Illeret Town from Loiyangalani.
"Yes a homeguard was killed after the lorry driver failed to stop prompting the gunmen to open fire," Mr Wanjala told the Nation on the phone.
The lorry driver sped off and reported the incident at Illeret police post.
Mr Wanjala said they have not established the motive behind the attack adding that no arrest has been made.
"We have launched investigations into the incident and are asking wananchi to co-operate with security personnel," Mr Wanjala said.