A gang of armed men killed four policemen in Sabongida Ora, a community in Owan west local government area of Edo state.
The security operatives were said to be on a routine patrol when the bandits swooped on them around 6pm.
The four policemen were ambushed, killed and burnt in their patrol van.
Three of the victims were burnt beyond recognition.
Ibrahim Idris, inspector-general of police, has directed a thorough investigation into the killings.
Jimoh Moshood, acting spokesman of the force, announced this in a statement in Abuja on Monday.
Moshood said the police would pay N5 million naira to anyone who provided information that could lead to the arrest of the remaining perpetrators of the Abuja killing and Sabon Gida Ora attacks.
Seven policemen on stop-and-search duty on July 3 were ambushed and killed by suspected gunmen at a roundabout in Galadimawa area of Abuja.
Godwin Obaseki, the governor, the unprovoked attacks on men and women of the police force and sister security agencies was unacceptable.
He said the state’s security architecture would create roles for communities and local groups as well as the organised private sector to support security agencies in eradicating crimes across the state.