The lawmaker from the Labour Party, representing Oorelope Constituency, was until his death the Chairman, House Committee on Information, Public Relations and Security.
He was killed in front of his house in Alakia area of the state as he alighted from his car to open his gate.
Three gunmen on a motorcycle trailed him to the house and shot him severally after a brief argument, a family source said.
Five Million Naira Bounty
In an attempt to quicken the arrest of the killers, the state Governor, Abiola Ajimobi, placed a five million Naira bounty on the heads of the gunmen responsible for the murder of the lawmaker.
The State Commissioner of Police, Leye Oyebade, said in a statement he issued on Sunday that the arrest was made possible by a combined team of Intelligence Response Team of the Inspector General of Police, Ibrahim Idris and detectives from the Oyo State Police Command.
The statement read: “Refer to gruesome murder of Honourable Gideon Aremu on July 1, 2016 by some gunmen who made away with his Samsung phones and some money. I wish to inform you that four suspects have been arrested in connection with the crime.
“The arrest was made possible by combined efforts of the Intelligence Response Team of the Inspector General of Police, Ibrahim Idris and detectives from the Oyo State Police Command”.