A public defender for Dean Jay Fletcher filed a motion Thursday saying the government is illegally keeping the currency.
U.S. marshals brought Fletcher to Honolulu last month after he allegedly escaped from a Tonga jail and sailed to American Samoa.
Court documents say he was indicted on a murder charge in the July death of his wife, Patricia Linne Kearney.
Assistant U.S. Attorney Larry Butrick says the government seized the money in accordance with a treaty with Tonga. He says the cash is worth about $10,000.