MIAMI – A Pentagon defense attorney is invoking a recent civilian court decision in a bid to get the military’s Sept. 11 death penalty case dismissed at Guantanamo.

Navy Cmdr. Walter Ruiz filed the challenge Friday on behalf of Mustafa al Hawsawi, 44, who is accused of helping some of the Sept. 11, 2001, hijackers with financial and travel arrangements to the United States.

He faces a military tribunal along with the accused 9/11 mastermind, Khalid Sheikh Mohammed, 47, and three other alleged plotters.

The filing, still under seal at the Pentagon’s war court, is the first known challenge to the military commissions system since a civilian court on Oct. 16 tossed out the 2008 conviction of Osama bin Laden’s driver in a ruling that disqualified material support for terrorism as a retroactive war crime.

In it, Ruiz said, he seeks dismissal of the case and argues that the 9/11 judge, Army Col. James Pohl, should adopt the same “ex post facto” interpretation of the U.S. Court of Appeals for the District of Columbia Circuit when it vacated the conviction of driver Salim Hamdan.

The 9/11 accused are charged with different crimes in a more up-to-date format of the court, which was reformed by President Obama after he took office. Hamdan was convicted during the George W. Bush years. But Ruiz said in a statement describing his filing, “The Hamdan decision strikes at the heart of an already frail and unsettled military commissions system.”

A notation on the sealed docket indicated that Pentagon lawyers for another of the Sept. 11 accused, Mohammed’s nephew, Ammar al Baluchi, 35, joined in the filing.