The tearful mother of the only known U.S. prisoner of war said Saturday she was feeling “very optimistic” about his eventual release after his Taliban captors offered to exchange him for prisoners at Guantanamo Bay.

Army Sgt. Bowe Bergdahl’s mother, Jani, spoke to about 2,000 people gathered in Hailey, his hometown, in a city park where he played as a child. Bergdahl, 27, was taken prisoner in Afghanistan on June 30, 2009,

About 400 in the crowd arrived astride motorcycles, adorned in leather and patches commemorating America’s military missing in action. Buses also brought POW-MIA activists from as far as Elko, Nev.

Jani Bergdahl, then her husband Bob, who accompanied the motorcycle procession on his son’s 1978 dirt bike, spoke for a combined 15 minutes about rejuvenated hopes that their son’s now-four-year ordeal will soon come to a joyful close.

“We are feeling very optimistic this week,” Jani Bergdahl said before addressing her son directly. “Bowe, we love you, we support you, and are eagerly awaiting your return home. I love you my son, as I have, from the first moment I heard of you, the never-ending, unconditional love a mother has for her child.”

Though yellow ribbons on Main Street trees and “Bring Bowe Home” placards in Hailey shop windows are a constant reminder of the 27-year-old Bergdahl’s captivity, organizers of the event said the Taliban offer lent an addition element of urgency — and hope — to Saturday’s gathering.

Many in the crowd said they were Vietnam veterans; some of them supported the proposed prisoner exchange without reservation.

“Give them their guys and get our guy home,” said David Blunt, of Elko, Nev., who served as an Army medic in Vietnam.

Bergdahl is believed held somewhere in Pakistan. The Taliban said they would free him in exchange for five of their most senior operatives at Guantanamo Bay, the American installation in Cuba that has housed suspected terrorists since the Sept. 11, 2001, terror attacks.

The militant group’s exchange proposition came just days ahead of possible talks between a U.S. delegation and Taliban members.

Bob Bergdahl urged those gathered to remember everyone, regardless of nationality, who had suffered during the 12-year conflict in Afghanistan.

He described his son as “part of the peace process.”

“I wish she was the only mother that was suffering in that way,” Bergdahl said of his wife. “Mothers all over the world are suffering because of this war, and I don’t forget that for even one day.”

He also addressed his son’s captors in Pashto, the Afghan language he has learned since Bowe Bergdahl went missing.

Both mother and father talked of Bergdahl as an adventurer, a young man who once helped crew a sailboat through the Panama Canal, disembarked in San Francisco and then rode a bicycle south along the Pacific Ocean to meet family in Santa Barbara, Calif., 350 miles away.

He joined the military at 22 because “he honestly thought he could help the people of Afghanistan,” Bob Bergdahl said.

On June 6, the family said it received its first letter from their son in his handwriting in four years, ferried through the International Committee of the Red Cross.

The circumstances of his capture aren’t completely clear, though U.S. officials in 2009 said a soldier had been taken after walking off his base following his duty shift.