The police say the suspects had previously been arrested and arraigned in court for other crimes but were released.
The police in Lagos State have arrested three alleged gang members from Lagos, Oyo and Delta states in connection with the robbery and murder of Adeniyi Sanni, an aide to the senator representing Ogun West, Solomon Adeola.
The three suspects involved in the alleged murder of the senator's aide were paraded on Monday at the police headquarters in Lagos.
Mr Sanni was shot dead on his way home and his corpse was later dumped close to a military barrack around Toyota bus stop in Oshodi, Lagos in the early hours of 5 August.
According to the senator, an investigation of the incident revealed that Mr Sanni was shot by some yet-to-be-identified officers of the Nigerian Army monitoring checkpoints in the Ikeja axis of Lagos State.
The suspects paraded on Monday by the police are Fred Azeez Okunnu, 43, Lucky Michael, 33 and Adedigba Segun 26. The police said the incident occurred between 1 a.m. and 2 a.m. on 5 August.
How the aide was murdered
According to the police, the suspects flagged down the deceased's car and requested to see his vehicle documents. One of the men was dressed in military uniform.
"In this incident, after seeing the papers, they insisted on taking the victim to their base. Once they entered the vehicle, it dawned on Mr Sanni that they were robbers," Idowu Owohunwa, the police commissioner, told journalists.
"He called out for help, which made the robbers shoot him thrice and further stabbed him. They dropped his corpse by the roadside and drove to Kuto, Abeokuta where they cleaned up the blood stains in the rear seats of the vehicle and later the same night proceeded with the vehicle to the border town of Chikanda in Kwara State where the criminal receiver took delivery of the car.
"The suspects adopted the use of military fatigue to beat checkpoints."
The police said they recovered one Brownie pistol with three rounds of live ammunition, one Beretta pistol with three rounds of live ammunition, one locally made cut-to-size pistol with 6 live cartridges, six expended cartridges, military gear (military camouflage vest, military jungle hat, military holster, jungle boots), and one Red Honda CRV with registration number EKY 276 JD, also snatched from a yet to be identified victim.
Police investigation revealed that the gang which is being armed by one Alhaji (based in Benin Republic) specialised in robbing motorists of their unregistered vehicles.
The gang have been successful in five previous operations, the police said.
"Further investigation has revealed that the said Alhaji has other cells operating across the country," Mr Owohunwa said.
"Being a transnational crime, the Command is involving the Interpol for the apprehension of this criminal receiver and financier."
The police said the suspects operate by stationing one gang member some metres from Berger bus stop to spot unregistered vehicles.
"The spotter then calls his gang members who are dressed in military fatigues and stationed somewhere around Berger bus stop to inform them of the approaching vehicle," he said.
"Once they stop their victim, they request for the vehicle custom papers, as they would need to clear security and customs checks."
The police also said that the suspects had previously been arrested and arraigned in court for other crimes before their release and eventual rearrest.