Police on Saturday seized two boxes containing a 'black' substance, reported to be explosive material, from the vicinity of one of the blast sites.
"We have certain leads on the blasts that we are working on. Some substance has been collected from one of the blast sites. But it will be too premature to comment on it till they are verified," Inspector General of Police (Nasik range) PK Jain said.
"The substance is being examined by forensic experts and bomb squads from central and state agencies," Jain, who is heading a special team investigating the blasts, added.
Forensic and bomb experts from the elite National Security Guards (NSG), camping in Malegaon since Friday night, are analysing the contents of the two boxes, the official said.
"Besides trying to find out what the substance is, forensic experts are trying to find out the modus operandi of the bombers and the nature of the explosive used in the explosions," said a senior official of the Mumbai Police's crack Anti-Terrorism Squad (ATS).
ATS is working with the Malegaon police and the Intelligence Bureau (IB) to investigate the blasts.
Malegaon was rocked by a series of explosions at a Muslim graveyard, located close to a mosque, that killed 38 worshippers and injured 190 minutes after the Friday prayers.
Investigators believe that the terror perpetrators had placed explosives on bicycles, as most worshippers who attend the Friday prayers ride bicycles.
"We are trying to trace the bicycles on which the explosives are believed to have been placed. We are trying to trace from where these cycles were bought as the cycles used in the blasts are apparently new," the ATS official said.
"We have some eyewitness accounts and the details of their statements are being verified and corroborated with other intelligence inputs we have gathered," the official disclosed.
He, however, did not elaborate.
"We are trying to ascertain if there are any similarities with the July 11 serial blasts in Mumbai," he said.
The ATS is also investigating the trail of explosive hauls in Maharashtra, the country's most industrialized state, in the recent past that could prove a connection between the Malegaon and Mumbai bombings.
The ATS had seized some 30 kg of RDX in Aurangabad on May 10, and a week later in Malegaon and Nasik.