"We have got very good leads from the sketch of the suspect. We have information that the suspect is from either central or northern parts of the country. That is the reason why we have spread our teams in these areas to trace the suspect," said a senior ATS official.
The teams of Maharashtra ATS and Mumbai Crime branch had been fanned to various states including Madhya Pradesh, Delhi, Rajasthan and Gujarat in a bid to get "solid leads" in the case, he added.
The suspect was allegedly involved in the blast at Zaveri Bazaar.
20 people were killed and over 130 injured in the triple blasts at Dadar, Zaveri Bazaar and Opera House on July 13.
The sketch was circulated only to select investigators, who are part of the 12 core teams formed to probe the blasts, besides a few top informers.
The ATS has so far verified incoming and outgoing records of over a lakh phone calls, the official said, adding some numbers are under their scanner and their veracity being ascertained.
Asked if these suspicious calls were either made to Madhya Pradesh, Kolkata or Gujarat, where ATS teams are working in a full swing for leads, the official refused to comment.
The sketch was prepared on the basis of eye witnesses` account after police showed them the footage pertaining to the blast at Zaveri Bazaar.
A joint team of Mumbai Police and Maharashtra ATS has also questioned suspected IM operative Danish Riaz in Gujarat in connection with the Mumbai triple blasts.
Danish was arrested from Vadodara railway station on June 21 in connection with the 2008 Ahmedabad blasts.