Headley, who has pleaded guilty to his role in planning the Mumbai terror attacks, had taken his wife and kids on a vacation during which he received several text messages from Mir seeking to know the peak hours at Mumbai train stations.
"In between Headley's fourth and fifth trips to conduct surveillance in India, Headley met with Sajid Mir on multiple occasions."
"During the first meeting with Sajid, which took place in Rawalpindi, Sajid told Headley that the Mumbai attacks would take place in the next few weeks," according to the transcripts of a Headley interrogation by the FBI, which was unsealed this week at the direction of the Chicago court.
Headley met again with Sajid a short time later and was told by the Lashkar commander that the attack was postponed until at least September 2008 because they needed to wait for calmer waters.
According to the transcripts of the FBI questioning of the 26/11 accused, Headley said a few days before Pervez Musharraf resigned as president of Pakistan he took his wife and kids to a mountain range between Muzzafarabad and Lahore for a short vacation.
"While Headley was with his family he received numerous text messages from Sajid regarding the train station in India where Headley had conducted surveillance," it said. Headley provided the details to Mir.
"Headley believed this was in about August of 2008," the FBI said.
"Sajid wanted to know the busy and slow times at the train station. Headley said he provided the information to Sajid and asked why Sajid wanted to know. Sajid did not provide an explanation to Headley," the FBI said.
In Headley's meeting with Tahawwur Hussain Rana in December 2008, Rana expressed happiness that India's incompetence was for everyone to see in the aftermath of the attacks, the FBI said.
During the discussion of the extensive media coverage of the Mumbai attacks, Headley apologised to Rana for using his office as a cover in India and told Rana that he owes him.
"Headley told Rana that on a personal level he felt this (Mumbai attack) evened the score between himself and India. Headley said he was referencing the fact that India bombed Headley's school in Karachi in about December of 1971," the court document said.