The police in Oyo State on Thursday vowed to arrest the killers of the commander, Special Anti-Robbery Squad in Saki, Mr. Sheu Magu.
The police officer and an informant were allegedly killed by Fulani herdsmen in the area on wrdnessay.
The herdsmen had surrounded the police team with cows before attacking them with machetes.
Some policemen escaped but Magu and the informant were killed.
They had gone to Saki based on information that herdsmen were terrorising residents of Saki.
Four suspects were immediately arrested.
Commissioner of Police, Oyo State, Mr. Abiodun Odude, said in Ibadan that more suspects would be arrested.