: Laden but all were released "for lack of evidence". --Stephen V Cole

India is convinced that Pakistani intelligence (the ISI) was behind the hijacking of an Indian airliner from Nepal to (eventually) Afghanistan. Indian intelligence has reported the following items, although like all intelligence agencies they have been loath to explain the "sources and methods" used to gather the information:
@ the hijackers have all been identified as Pakistani citizens.
@ the hijackers were in continual contact with Ahmad Syeed Shaikh, a Pakistani who lives in England and has British citizenship. (Shaikh's son was one of the three radicals released by India to win release of the passengers.) Indian intelligence monitored communications between the hijackers and Shaikh, and between Shaikh and the ISI.
@ the hijackers were trained by the ISI at a camp in Pakistani-controlled Kashmir. They were given access to an Airbus airliner of the same type they hijacked and trained for weeks in how to take it over. They were extensively briefed in aircraft operations so they could detect any unusual activities by the pilots during landing or takeoff that might indicate that an attack was imminent.
@ the airport staff in Katmandu was heavily bribed by known Pakistani agents. One Pakistani diplomat in Nepal has been expelled from that country for his part in the operation.
@ the training the hijackers received included how to terrorize the passengers without major bloodshed (one passenger was stabbed to death) and were noted as being unusually calm and in control during the five-day ordeal.
@ Indian police arrested four ISI agents in Mumbai who provided ground support for the operation. All have talked under torture, revealing details of the plan.
@ of the 36 prisoners that the hijackers demanded the release of, 32 were Pakistani citizens. The Pakistani government had twice requested the release of Maulana Azhar, who was one of the three actually released.
@ Taliban gave the hijackers a vehicle and 10 hours to leave the country. The only place they could have reached in ten hours was Pakistan. 
@ the ISI is claimed by India to have been involved in seven previous hijacking incidents against Indian airliners, as well as hundreds