Gunmen on Sunday abducted Andy Ehanire the younger brother of the minister of health Osagie Ehanire in Benin City, Edo State.
Three policemen were also shot by the gunmen in an attack at Ogba Zoological Gardens, Benin City.
Mr Ehanire is the managing director of the gardens.
Police spokesperson in Edo Moses Nkombe confirmed the development to reporters on Monday.
The slain policemen were posted to the garden to provide security for fun-seekers at the zoo and nature park.
The killing disrupted activities at the zoo as many fun seekers scampered for safety, the News Agency of Nigeria (NAN) reported.
“Our men are working on that (the incident), though we have not made any arrest,” the police spokesperson said.
The remains of the police officers have since been deposited at the morgue of the Benin Central Hospital.