India claims that the Mumbai bombings were masterminded, planned, and financed by the Pakisani ISI (their monolithic state intelligence service.) The Pakistanis deny everything, of course, but the Indian investigators seemed to have a pretty damning case.
What effect another Indo-Pakistani war would have these days is anybody's guess, now that:
1) Pakistan and India both have limited nuclear capability.
2) NATO has boots on the ground on Pakistan's northern border.
3) The nation-shaped powderkeg of Iran is on Pakistan's western border, and may get all friendly and fellow-Muslim if the balloon goes up.