Ten days after Terrible Tuesday’s serial blasts, the Maharashtra Anti-Terrorist Squad (ATS) claimed this morning to have achieved a “breakthrough” with the arrest of two persons from Bihar and one from Navi Mumbai in connection with the blast at Matunga, one of the seven on 7/11.

ATS officials said they are relatives and were arrested after investigators received information from “reliable sources” about their alleged involvement.

Those arrested: Kamal Ahmed Ansari (32) and Khalid Aziz Ronak (24) from Basupatti village in Madhubani district of north Bihar and Mumtaz Ahmed Maqbool Ahmed (38) from the Thurbe suburb of Navi Mumbai.

Kamal is Mumtaz’s brother-in-law and Khalid a relative. ATS claimed to have recovered from Kamal half a kilogram of explosive substance in powder form, suspected to be gunpowder.

Ansari was arrested by the Delhi Police some years ago for the possession of an AK-47 rifle, said ATS chief Joint Commissioner of Police K P Raghuvanshi.

When the three were produced before Additional Metropolitan Magistrate A V Shettye, the ATS sought police custody until July 24 but the magistrate, citing the seriousness of the charges—including murder, attempt to murder, criminal conspiracy, Arms Act—granted custody until July 30.

“Investigations have till now revealed involvement of terror groups from Nepal and Bangladesh and, in turn, point at direct or indirect involvement of Pakistan,’’ said Raghuvanshi. In the Maharashtra Assembly, Deputy Chief Minister R R Patil was more direct: ‘‘Pakistan has asked for proof. We have enough evidence to prove that terrorist organisations based in Pakistan are behind it (the serial blasts).”