The names of trainers and the places where meticulous training took place are also known to the government, the sources said.
The United States is believed to have even more evidence, some of which it has shared with India, they said.
Chairman of US Joint Chiefs of Staff Admiral Mike Mullen, who was in Pakistan on Wednesday, is believed to have told his Pakistani interlocutors that Washington had enough evidence to show a Pakistani hand in the attack, the sources said.
Sources in New Delhi also refuse to believe that the Pakistani army did not have knowledge of the Mumbai operation given that the ISI is controlled by it.
At the same time, sources do not believe that the civilian government in Pakistan is involved in the attack. In fact, one view is that the civilian government itself may be a target of the strike which may be used by the army to heighten tensions with India to return to power.
Washington has asked Pakistan to crackdown on Lashkar e Tayiba, which now goes under the name of Jamaat ud Dawa, and to arrest its chief Hafeez Mohammed Saeed because it has evidence of their involvement in the attack, the sources said.
The attack was planned, equipped and organised in Pakistan where the terrorists were trained and provided logistical support.
Contrary to the version that the terrorists used a hijacked Indian fishing boat to reach Mumbai after sailing from Karachi, the view in the capital is that much more sophisticated means were used.
The sources spoke of a clear disconnect between the Pakistani civilian government and the all-powerful military establishment, which is causing difficulties for India in dealing with the situation.
Islamabad's about-turn on sending the director general of ISI to India is cited as an instance of this disconnect.
During a telephone conversation with Prime Minister Manmohan Singh after the Mumbai attack, President Asif Zardari had referred to an earlier Pakistani proposal for a meeting between the ISI chief and the head of India's external intelligence agency, RAW.
Singh told Zardari that this was acceptable to India, after which the Pakistani government had announced that the ISI head would travel to India.
After a post-midnight call on Zardari by Army chief Gen Ashfaque Kayani this decision was reversed with the President taking cover under a "miscommunication" with the Indian prime minister. Instead it was decided to depute a director-level officer to India.
When the terror attack took place Pakistan Foreign Minister Shah Mehmood Qureshi was in India and had consciously decided not to cut short his visit. However, the Indian government was told at 2.30 am that a special aircraft was being sent less than four hours later to take him back to Pakistan.
In what observers see as a clear message to the civilian government, the Pakistani army chief's plane was sent to Delhi to pick up Qureshi, who boarded the flight around 7 am.