Farooq Takla a key aide of Dawood Ibrahim who was arrested on Thursday facilitated the escape of several accused following the 1993 Mumbai serial blasts officials said.
They also said Takla used to facilitate the travel of men from Dubai to Karachi without immigration checks, for their training in making bombs and use of sophisticated weapons.
Takla, 57, was arrested in Delhi by the CBI on Thursday upon his arrival from Dubai.
He was a hawala operator in the Gulf since the early 1990s and had not taken shelter in Pakistan, like his mentor Dawood, a security official said.
The gangster had left Mumbai after a bitter rivalry with the Arun Gawli gang. In September 1992, Shailesh Haldankar of the Gawli gang was killed by the Dawood group while he was recuperating in JJ hospital.
It was allegedly done to revenge the killing of Dawood's brother-in-law Ibrahim Parkar, who was killed near his residence in 1992 allegedly by two members of the Gawli gang. Takla was a key facilitator for stay and opening businesses for all the 1993 Mumbai blasts accused, who had left India before and after the attacks in the metropolis, the official said.
While Dawood and his family, another Mumbai blasts accused Tiger Memon and his family had left Dubai after a few years and taken shelter in Pakistan, Takla continued to live in the Gulf with his ever-increasing 'hawala' trading, another official said.
Takla has been mostly operating from Dubai and a few other places in the Gulf with an assumed name.
The CBI had got the Interpol to issue a Red Corner Notice against Takla in 1995.
Mohammed Farooq, better known as Farooq Takla, arrived in Delhi from Dubai and was arrested by the CBI when he was at an immigration counter at the Indira Gandhi International Airport on Thursday morning.
While the CBI declined to comment on how he reached Delhi as an Interpol Red Corner notice was pending against him, officials said Farooq was deported from the UAE with the help of central intelligence agencies and put on a flight to Delhi.
Officials said India's engagements with West Asia have increased in last few years and the results were showing with the deportation of several gangsters and wanted terrorists in recent past.
Police officials in Mumbai who investigated the 1993 serial blasts case said Farooq was a big catch for the probe agencies as he was among those who were aware of the serial blasts conspiracy.