The policeman was in one of two vans transporting maize flour before they were ambushed.
According to witnesses, the armed robbers who were riding on a motorbike posed as customers at Bahajajj Grocery before shooting the officer twice in the head and abdomen.
Confirming the incident, Kwale County Police Commandant Kenneth Kimani said a contingent of GSU and Administration Police officers have since been dispatched to the area and a major operation to track down the gangsters has been launched.
“The operation is going on and more officers will join their colleagues later.” Kimani added.
A similar attack was carried out last year at Kombani in Kwale County when an officer was shot and wounded in the head and his AK 47 rifle stolen by gunmen on a motorbike.
The attack last year came a week after police recovered an AK 47 from the Musa Mosque in a raid to break up a controversial meeting. The attack was believed to have been staged to replace the recovered weapon.
Grenade attacks and shootings targeting security forces have become common in Kwale County since Kenya sent its troops to Somalia in 2011.