The suicide bomber was able to breach the security checkpoints in the heavily guarded national highway to ram his Tata Sumo into one of the buses in the CRPF convoy.

It is usual to restrict the movement of civilian traffic in the state during movement of such convoys

There were 2,547 CRPF Jawans who were traveling in the convoy with 78 vehicles. The size of the convoy was unusual. Usually, around 1,000 Jawans travel in such convoys. The preparation for this unusually large convoy might have reached to the terror group. As the got the information, they were able to plan and executed the attack.

Indian intelligence agencies have already received inputs that Jaish-e-Mohammad was arranging large quantities of a powerful explosive but the exact details of their plan were not known to them, which delayed any action.

Jaish-e-Mohammad was looking to avenge the killing two of its high profile members – Mohammad Usman and Talha by the security forces last year. The security agencies should have expected an attack at any moment.

This is similar to the lapse which eventually lead to Pathankot attack. Even after receiving information before the attack, proper action couldn’t be taken.