Jim Michaels

USA TODAY

WASHINGTON — The U.S. Army is launching a new review into why Sgt. Bowe Bergdahl left his post and how he was subsequently captured by the Taliban.

The new investigation comes amid mounting allegations from fellow soldiers and others that Bergdahl deserted his post and put additional troops at risk when they searched for him.

The review "will include speaking with Sgt. Bergdahl to better learn from him the circumstances of his disappearance and captivity," Army Secretary John McHugh said in a statement.

Bergdahl was released after five years in captivity as part of a secret agreement announced last weekend. In return, the United States released five Taliban detainees held at Guantanamo Bay, Cuba, to the government of Qatar, a small Persian Gulf state that had helped broker the deal. They are to remain in Qatar for a year.

The Army had completed an earlier investigation into Bergdahl's actions that involved interviewing fellow soldiers and other witnesses.

The Pentagon said that investigation remains classified, but a defense official said investigators believe he walked off his post without authorization before he was captured. The official, who declined to be identified because he was not authorized to speak about the case, would not provide further details about the day he disappeared.

The prisoner exchange has come under withering criticism from some servicemembers, who said he broke faith with his fellow soldiers and shouldn't be treated as a hero.

"We all served together, and we were all in it together over there, and he broke that bond by leaving us," former Army sergeant Josh Korder said on NBC's Today show.

Members of Congress also have questioned whether Bergdahl deserted his post. Others criticized the deal, saying it will encourage militants to capture Americans and allow the Taliban released in the deal to return to the battlefield in Afghanistan.

House Speaker John Boehner said the deal could put diplomats and servicemembers serving overseas at greater risk. "One of their greatest protections – knowing that the United States does not negotiate with terrorists – has been compromised," Boehner said in a statement.

Senate Intelligence Chairwoman Dianne Feinstein, D-Calif., said: "I certainly want to know more about whether this man was a deserter."

President Obama defended the prisoner swap, referring to the bedrock military commitment to return all soldiers from the battlefield.

"Whatever those circumstances may turn out to be, we still get an American soldier back if he's held in captivity," Obama told reporters. "Period. Full stop. We don't condition that."

Bergdahl remains at the military hospital in Landstuhl, Germany, where he is under the care of psychologists who specialize in reintegrating prisoners of war. He is in stable condition, said Army Col. Steve Warren, a Pentagon spokesman.

U.S. officials say the first priority is ensuring Bergdahl's health and successful reintegration into society after so many years in captivity. It is not clear how long it will be before officials can ask him about the circumstances of his capture.

"Our first priority is ensuring Sgt. Bergdahl's health and beginning his reintegration process," McHugh said in the statement. "There is no timeline for this, and we will take as long as medically necessary to aid his recovery."

Military officials, however, also have begun to address the issue of holding him to account for any improper actions.

Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff, said in a Facebook post that Army leaders would "not look away from misconduct if it occurred."

"Let's be happy we got him home," said James Mattis, a retired four-star Marine general who led Central Command, which oversaw the wars in Iraq and Afghanistan. Now it will be up to the Army "to address any culpability on his part, if there is any," he said.

Contributing: Susan Davis