The Delhi Police's Special Cell on Tuesday busted a 'terror module' with the arrest of six men, including two terrorists trained by Pakistan's intelligence agency ISI.
Hiran was found dead in a creek in Thane on March 5, days after he claimed that the Scorpio with explosives found near industrialist Mukesh Ambani's house in south Mumbai.
According to the ATS, Mumbai police officer Sachin Waze, now suspended and in custody of the NIA, had played a key role and emerged as the prime accused in the Hiran murder case.
Their arrest came the day the Ministry of Home Affairs handed over the probe into the Hiran death case to the National Investigation Agency.
Hiren, the owner of the vehicle that was found containing explosives outside the house of Reliance Industries Chairman Mukesh Ambani, was found dead on March 5 in Thane.