Riyaz Kazi was called for questioning again by the NIA on Sunday and later placed under arrest.
The National Investigation Agency on Sunday arrested police officer Riyaz Kazi who was an associate of suspended cop Sachin Vaze, in connection with the case of an explosives-laden SUV found near industrialist Mukesh Ambani's residence, a police official said.
Kazi was called for questioning again by the NIA on Sunday and later placed under arrest, he said.
He was previously also questioned by the NIA in connection with the case of the SUV with explosives found near Ambani's residence in south Mumbai on February 25 and the subsequent death of Thane businessman Mansukh Hiran.
Kazi was shunted out of the Mumbai Crime Branch last month, the official said.
Earlier, in a CCTV footage, Kazi was seen entering a number plates shop in Vikhroli area here and having a conversation with the outlet's owner. He was also seen taking away a digital video recorder and a computer of the shop.
Kazi was also seen collecting CCTV footage from Vaze's housing complex in neighbouring Thane, the official said.
The probe agency suspects that Kazi assisted Vaze in obtaining fake number plates used for the SUV found with explosives near Ambani's residence in south Mumbai, he said.
Hiran, who was in possession of the SUV, was found dead in a creek in Thane on March 5.
The NIA arrested Waze on March 13 in connection with its probe into the case.
(With PTI inputs.)