Congressional investigators say the Pentagon violated the law when it swapped five Taliban leaders for Army Sgt. Bowe Bergdahl, who was held prisoner in Afghanistan for five years.
The nonpartisan Government Accountability Office says the Defense Department's failure to notify the relevant congressional committees at least 30 days in advance of the exchange broke the law.
The GAO also says the Pentagon's use of funds to conduct the transfer, when no money was available, was a violation of the Antideficiency Act which bars spending by agencies above the amount of money that Congress has obligated.
In May, five senior Taliban were released from Guantanamo Bay, Cuba, in exchange for Bergdahl, who had disappeared in 2009. Under exchange terms, the five Taliban are to remain in Qatar for a year.