The suspects were pararded on Wednesday by the State Commissioner of Police, Mr Kayode Aderanti at Ikeja, Lagos.
The four suspects are gang leader, Duke Odogbo, 38, Lawrence Kingsley, 31, Ebi Tosan, 20, and Ekelemo Kuete, 30.
Aderanti said exhibits recovered from the suspects include a Honda Accord 2008 model car, military fez cap, phones and 130 expended ammunition.
He said during the robbery operation, five people were shot dead, three policemen and two civilians.
The policemen killed were Inspector Bethel Agbobu, Sgt Odehohwo George and Cpl Imoisiu Ikechukwu.
The two civilians killed were Mr Sowemimo Kabiru and 15-year-old fish seller, Miss Sarah Ibikunle.
Aderanti said after the incident, he summoned a meeting of various commands and directed the Officer in Charge of the Special Anti-Robbery Squad, SARS, SP Abba Kyari to take charge of operations to fish out the suspects connected with the robbery.
He said the O/C SARS deployed advanced technology and human resources to Delta, Ogun, Ondo and Ikorodu, and in the course of the operations, one of the suspects, Odogbo the leader of the gang was arrested in Delta State.
Odogbos’s arrest led to the arrest of other suspects who will be charged to court soon after the police have concluded their investigations.