Agency declares Pentagon broke law in Bergdahl prisoner swap

(CNN) — The Pentagon broke federal law by exchanging five Taliban detainees for Army Sgt. Bowe Bergdahl without giving Congress enough of a heads-up, Congress’ independent investigative arm announced Thursday.

Susan Poling, the general counsel for the U.S. Government Accountability Office, wrote in a letter to several Republicans in Congress that the Pentagon should have notified “the relevant congressional committees at least 30 days in advance of the transfer.”

Moreover, Poling noted that the GAO also concluded the Defense Department broke the law by using “appropriated funds to carry out the transfer when no money was available for that purpose.”

Poling noted that her office wasn’t weighing in on Defense Secretary Chuck Hagel’s decision to carry out the prisoner swap, but rather his “responsibility to comply with a notification condition on the availability of appropriations to transfer individuals from Guantanamo Bay.”

A Defense Department official didn’t immediately return a CNN call Thursday for comment on the GAO’s conclusions.

Captured in Afghanistan early in the summer of 2009, Bergdahl was freed almost five years later in exchange for five men who were being held at the U.S. military prison in Guantanamo Bay, Cuba.

At the time of his release, the 28-year-old was the longest-held U.S. soldier since the Vietnam War.

The swap stirred sharp criticism, especially among Republicans who questioned whether the U.S. government might encourage its enemies to take more Americans captive. Others — including members of his unit — accused him of deserting his comrades in the midst of a war.

An Army fact-finding investigation conducted in the months after his disappearance concluded he left his outpost deliberately and of his own free will, according to an official who was briefed on the report.

There has been no definitive conclusion Bergdahl was a deserter. He met for two days earlier this month with an Army investigating officer who has been reviewing his case.

Unless he requests an extension, the investigating officer has until mid-August to complete the probe. A report would typically be issued about a month later.

As for Bergdahl, he’s back in the active military. Following his release in late May, the Idaho native underwent medical care and mental counseling at an Army hospital in San Antonio before taking a desk job at Fort Sam Houston, according to military officials.