The gelatin sticks found in an SUV near industrialist Mukesh Ambani's residence in Mumbai last month were procured by suspended police officer Sachin Vaze, NIA sources claimed on Wednesday.
However, they did not elaborate on the source of the explosives.
The National Investigation Agency (NIA), which is probing the case, has also found that Vaze along with his driver parked the SUV near Ambani's house, the sources said.
"The gelatin sticks, which were placed in the SUV, were procured by Vaze," a source said.
The NIA has CCTV footage that shows the presence of Vaze at the spot, the sources said.
As a part of the probe into the case, the NIA team is going to collect CCTV footage of the compound of the Mumbai police commissioner's office and surrounding areas, they said, adding that this will establish Vaze's movements and other aspects.
There were some attempts to tamper with the CCTV footage and digital video recorders (DVRs) of the police chief's office, but the majority of the footage is available, the sources said.
The probe agency is verifying whether the accused person (Vaze) destroyed any DVR of the Mumbai police commissioner's office and the surrounding area, they said.
Vaze allegedly tried to destroy the CCTV footage and DVRs of Saket society in neighbouring Thane, where he was staying, as well as of a shop making number plates in Thane by throwing them into some water bodies, the sources said.
The NIA on Sunday recovered a laptop, a printer, two hard disks, two-vehicle number plates, two DVRs and two CPUs from the Mithi river here with the help of divers, they said.
Vaze was arrested by the NIA on March 13.
The agency is probing the alleged role of Vaze in parking the explosives-laden SUV near Ambani's residence on February 25 and in the murder of businessman Mansukh Hiren.
The body of Hiren, who was in possession of the SUV, was found in a creek in Mumbra town of Thane district on March 5.