Mumbai: Desperately looking for a breakthrough in the city's triple blasts case, the Maharashtra ATS has extensively questioned an alleged Indian Mujahideen (IM) operative, who was arrested in a counterfeit currency case, with regards to the July 13 explosions.

"We have grilled Asrar Ahmed about the blasts (July 13 triple blasts) for long. But nothing much has yielded as of now," said an ATS official.

Asrar Ahmed Abdul Hamid Tailor alias Sagri (41), alleged member of the IM as well as SIMI, was arrested from outside Borivili railway station on Monday. The ATS in its remand application claimed that the computer trainer had received terror training in Pakistan.

Asrar's aide Haroon Rashid Abdul Hamid Naik, another suspected IM member, was apprehended earlier this month, in the fake currency case.

A relative of Haroon expressed fear that the ATS may falsely implicate him in the July 13 blasts.

"Haroon is innocent. The ATS senior officials are unwilling to tell us why he was arrested," the relative said.

"Some lower-rung police officials say Haroon was arrested for fake currency but senior officers are not telling us anything as to why he was arrested," the relative said.

The ATS has been burning the midnight oil searching for clues in the blasts probe. Though it has not openly stated which terror outfit was responsible for the blasts, the investigating agency suspects that the IM may have triggered the explosions.

At least 26 people were killed and several others were injured in the triple blasts at Dadar, Opera House and Zaveri Bazaar localities of the city on July 13.

The ATS has also claimed that Asrar had confessed to having been involved in the distribution of fake currency notes along with Haroon, to whom he imparted computer training.

According to the officials, Haroon had sent Asrar to Pakistan for terror training in 2000. Asrar had three criminal cases registered against him since 2006, including one with ATS.

Seeking the remand of Asrar, ATS on Tuesday told a local court that he is a trusted confidant of some of the absconding accused in the case being handled by it. The court remanded Asrar in ATS custody till next week.