Mumbai, Jul 17: The Anti-Terrorist Squad (ATS) on Monday said forensic reports have revealed the use of RDX, ammoniun nitrate and fuel oil in the seven blasts that rocked Mumbai on July 11.
ATS chief K P Raghuvanshi said that traces of explosives found at the blast sites were very small in quantity which led the forensic experts to take extra time to anaylse them.
The assistance of the National Security Guard and the Forensic Science Laboratory in Hyderabad was taken to come to a conclusion, he said.
Stating that investigations are at a critical stage, Raghuvanshi said the blasts were the handiwork of someone "beyond the border" but did not name any organization.
He denied media reports that two persons had been arrested by security agencies and said he was in touch with the police in Gujarat, Madhya Pradesh and Delhi.
Meanwhile, the ATS team has reached Tripura to question suspects. However, there is no confirmation on anyone being brought from Nepal for interrogation.
"It's premature to speak of information we have received, but we are working on all possible leads," Mumbai Police chief, A N Roy said.
"We believe the breakthrough will come soon," Roy added.
Prime Minister Manmohan Singh on Sunday had said that India's two-year-old peace process with Pakistan cannot move forward if terrorism "aided and abetted from outside" continues to claim lives in India.