The National Investigation Agency (NIA) on Thursday arrested former Mumbai Police cop Pradeep Sharma in the Antilia bomb scare case and the murder case of businessman Mansukh Hiran.

The arrest was made at the Mumbai office of NIA, just three hours after the NIA team conducted searches at the residence of Pradeep Sharma in Mumbai’s Andheri (east) area.

According to sources, Sharma was arrested on the basis of statements of other accused mentioning his name and evidence in form of technical data pointing towards his possible role in the terror and murder case.

Pradeep Sharma, known as an encounter specialist, was questioned twice earlier by NIA officials in connection with the case. He is known to be close to former Mumbai Police cop Sachin Vaze, who has been arrested by the central agency as the main conspirator in both cases.

Pradeep Sharma joined Mumbai Police as sub-inspector in 1983 and has been involved in over 300 encounters related to the Mumbai underworld, out of which, 113 shootouts are in his name.

After the arrest of Sachin Vaze and Vinayak Shinde in the Ambani car bomb scare case, the NIA was looking into the links between both accused and Pradeep Sharma. The friendship between Pradeep Sharma, Sachin Vaze, and constable Vinayak Shinde was known to many in the Mumbai Police force. Vaze and Sharma met for the first time at the Mumbai Police Commissioner's office and became good friends.

On Wednesday, the NIA had arrested two more persons in the case related to the recovery of an explosives-laden SUV from outside the south Mumbai residence of industrialist Mukesh Ambani in February this year. The duo, Santosh Shelar and Anand Jadhav, were produced before a special court which remanded them to NIA police custody till June 21 for further investigation.

During their questioning, sources say, NIA officials learnt about the role of Pradeep Sharma and a team was formed to conduct searches at his residence.

Shelar and Jadhav are also under the radar for their alleged role in the murder of Thane-based businessman Mansukh Hiran, who purportedly owned the SUV found outside Ambani's residence Antilia on February 25. Hiran’s body was found in a creek in Thane on March 5.

During his interrogation, Shelar has taken the name of two associates along with Pradeep Sharma. The two associates are linked to the Lakhan Bhaiyya case.

NIA sources said a larger conspiracy was being probed with the fresh arrests that have been made in the cases.