Headley will testify in any future prosecutions of fugitive masterminds such as Al Qaeda commander Ilyas Kashmiri and LeT's Sajid Mir, who is charged with a lead role in the Mumbai plot, Propublica.com quoted US Attorney Patrick Fitzgerald as saying.
Headley, a Pakistani-American, was the star witness in the recently concluded trial of Tahawwur Husain Rana, who was convicted by a Chicago court on two counts of terrorism related charges -- participating in the conspiracy of terror attacks in Denmark and providing material support to Lashkar-e-Tayiba.
Rana, 50, however, was found not guilty on charges related to the Mumbai terrorist attacks. He now faces a maximum jail sentence up to 30 years.
"Fitzgerald declined to discuss details of the case such as the politically sensitive decision to indict a suspected Inter-Services Intelligence officer who served as Headley's handler and is known only as Major Iqbal," ProPublica said.
At a news conference in Chicago last week, Fitzgerald vowed to bring the other six Pakistan-based defendants to justice who have been named in the indictment filed by federal prosecutors before the court.