"Dawood and Chhota Shakeel are the prime suspects. We will name them when we file the chargesheet in the case six months from now," a police official told IANS.
Earlier, Maharashtra Police had charged tainted Rajasthan Royals players S. Sreesanth, Ajit Chandila and Ankeet Chavan under the Maharashtra Control of Organised Crime Act (MCOCA) for their involvement in spot fixing in the IPL.
The three cricketers were arrested May 16 in Mumbai by Delhi Police for their alleged involvement in spot fixing for payments up to Rs.60 lakh each for giving away a pre-determined number of runs in an over.
Rajasthan Royals' owners have lodged a criminal complaint against the players while the Board of Control for Cricket in India (BCCI) has suspended them.
Delhi Police have arrested 26 people in connection with the IPL scandal. Of these, 18 have been sent to judicial custody, including the Rajasthan Royals' players.
Chavan was granted interim bail May 30 by a Delhi court to get married June 2. He has to surrender June 6.
After slapping stringent MCOCA against all the accused, Delhi Police Tuesday claimed that bookies like Ashwani Aggarwal alias Tinku Mandy were working at the behest of Dawood's gang.
Police claimed that they have enough evidence, including telephonic intercepts, to prove that the bookies used the underworld network in fixing IPL matches.
"We have telephonic intercepts in which some of the bookies had made calls to Dubai, Karachi and other cities of Pakistan to fix and alter betting rates," said the official.
"We got information in March that some people in India and abroad were involved in betting," said the official.
The official added that they have a "fit case" to invoke MCOCA.
"There is an organised crime syndicate linking underworld connection with bookies and players," said the official.
According to the official, one of the arrested bookies, Sunil Bhatia, is involved in criminal activities.
The official said one of the arrested bookies had threatened a player.
"The bookie told a player that he would teach him a lesson when he comes to Mumbai," the official said, adding that the same bookie has two cases against him, of which the court has taken cognizance.
Police also moved court seeking a production warrant of Ramesh Vyas, arrested by Mumbai Police in connection with a case of betting.
As Delhi Police had ensured that the accused would not get bail by slapping MCOCA, they were investigating leads to nab Hyderabad-based Mohammed Yahya, who could lead to another cricket team whose players were allegedly involved in spot fixing.