Another terrorist group claimed responsibility. Indian officials however through accusations in the direction of Pakistan. Pakistan strongly denies.
Spark can start a fire, what can be started when two nuclear states rediscover their animosities, which their respective armies have never really buried too far.
A conspiracy theory would say that those that planed this attack have played on the "good old neighbourly" hatred in order to spark a broader conflict and destruction that could follow should the pieces lay well on the board.