Nearly 2.5 kg of RDX was used in the two bombs suspected to have been dropped by Pakistan-based terrorists of Lashkar-e-Tayiba on the Indian Air Force station in Jammu through drones on June 27, officials said on Monday.
The National Investigation Agency took over the investigation into what was the first instance of Pakistan-based terrorists deploying drones to strike vital installations in India on June 29.
Two IAF personnel were injured in the explosions that took place within six minutes of each other. The first blast ripped off the roof of a single-storey building at the technical area of the airport manned by the IAF in Satwari on the outskirts of Jammu. The second one was on the ground.
The probe by the investigators pointed to the involvement of LeT terrorists who were actively assisted by the Inter-Services Intelligence of Pakistan in carrying out the covert operation, the officials said.
They said the probe indicated that the drones with bombs, containing nearly 2.5 kg RDX, came from across the border.
The aerial distance from the Jammu airport to the international border is 14 km.
The use of RDX in the explosion was confirmed by experts after samples from the scene were sent for examination. While one of the bombs was laced with 1.5 kg of RDX, the other contained nearly 1 kg of RDX, the officials said.
On July 2, Jammu and Kashmir Director General of Police Dilbag Singh said the involvement of Pakistan in the drone attack cannot be ruled out as there is a strong suspicion about the role of LeT in it.
Singh had said the use of armed drones by Pakistan-based terrorists is a serious threat to the security system and there was a need to have a relook at the security of vital places and persons.
"We have got very serious and strong suspicions that LeT is involved in this case... Since LeT is involved and the outfit is run from Pakistan, so in a way, Pakistan's involvement cannot be ruled out," the police chief had told reporters on the sidelines of a function in Kathua district.
To what extent Pakistani agencies are involved would be known only when the investigation proceeds further, he had said.
The DGP said over a dozen incidents had taken place earlier wherein the LeT was involved in dropping weapons, ready-made IEDs and narcotics using drones.
Singh said it is very much possible that the drones came from across the border.
"In the earlier drone droppings, the drones covered a distance of 10 to 15 km and the aerial distance of the Jammu airport (from the international border) is not more than that. The particular route which is suspected to have been taken by the drone if it had come from across (the border) also comes within the range of 15 km," he had said.
Singh said there have been incidents of drone droppings in Akhnoor and Arnia on the outskirts of Jammu and Samba and the initial indications and questioning of people who have been caught pointed towards it.