Zahid Patni, prime accused in the July 28 Ghatkopar blast, has returned to Mumbai from Dubai at the behest of his family.
The police have questioned Patni, but not arrested him so far, Additional Commissioner of Police Rakesh Maria told rediff.com on Wednesday.
Mumbai blasts: The complete coverage
He is also suspected being involved in the August 25 bomb blasts at Zaveri Bazaar and Gateway of India in Mumbai.
