WASHINGTON (CNN) -- Congressional investigators checking for political motive in the Justice Department's dismissal of selected U.S. attorneys last year now have a federal court order to hear from a former high-level government attorney, Monica Goodling.

In a request for immunity from prosecution filed and granted within hours Friday at U.S. District Court, the House Judiciary Committee said the protected testimony could shed light on circumstances "surrounding recent terminations of certain United States attorneys, representations to Congress regarding those circumstances, and related matters."

The panel's leadership believes Goodling took part in "crucial discussions" leading to a "termination list" that was then "refined and finalized," according to a letter last month from committee Chairman John Conyers, D-Mich., that was sent to Attorney General Alberto Gonzales.

The letter was included in Friday's court filing.

Reacting to the judge's order, Conyers issued a statement Friday saying, "Monica Goodling is a critical witness to this ongoing investigation. We look forward to hearing her testimony as promptly as possible."

Hogan is protecting Goodling against criminal action as a result of what she discloses, but she could still be prosecuted if she provides false statements, commits perjury, or otherwise fails to comply with his order.