The lawyer further requested that the details of that immunity deal be provided as a sealed, "ex parte" document, concealing them from the public.
U.S. District Court Judge Emmet Sullivan had requested language of Bryan Pagliano's immunity deal after learning that he intended to take the Fifth
at a deposition that was originally scheduled to take place Monday but has since been postponed.
Pagliano, who helped set up and maintain Hillary Clinton's private email server, was subpoenaed by the conservative legal watchdog group Judicial Watch as part of a Freedom of Information Act lawsuit against the State Department.
He was offered an immunity deal
late last year in order to offer testimony as part of an ongoing FBI investigation into the email server.
But Pagliano's lawyer, Mark MacDougall, said in a court filing Tuesday that DOJ "has not authorized a grant of immunity for Mr. Pagliano in connection with any other matter, including this civil case."
"The potential for self-incrimination here is sufficient to justify Mr. Pagliano's intention to assert his Fifth Amendment rights," MacDougall added, noting, "Mr. Pagliano's prospective deposition will inevitably cover matters that might 'furnish a link in the chain of evidence needed to prosecute.'"
"Indeed," MacDougall continued, "the mere fact that the government was willing to offer Pagliano 'use' immunity here in exchange for his testimony indicates that his fear of prosecution is more than fanciful or speculative."
Judicial Watch, the plaintiff in the FOIA case, has until Friday to argue for the immunity deal to be made public.
CORRECTION: This story has been updated to reflect Judge Emmet Sullivan's title.