WASHINGTON (AP) — The nation’s top military officer said Tuesday the Army could still throw the book at Sgt. Bowe Bergdahl, the young soldier who walked away from his unit in the mountains of eastern Afghanistan and into five years of captivity by the Taliban.Charges are still a possibility, Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, told The Associated Press as criticism mounted in Congress about releasing five high-level Taliban detainees in exchange for Bergdahl. The Army might still pursue an investigation, Dempsey said, and those results could conceivably lead to desertion or other charges.Congress began holding hearings and briefings into the deal that swapped Bergdahl for Taliban officials who had been held at Guantanamo Bay, Cuba, and several lawmakers said that President Barack Obama didn’t notify them as a law governing the release of Guantanamo detainees requires. White House staff members called key members of Congress to apologize, but that didn’t resolve the issue.Since Dempsey issued a statement Saturday welcoming Bergdahl home, troops who served with the soldier have expressed anger and resentment that his freedom — from a captivity that they say he brought upon himself — may have cost comrades’ lives.