Robert Bergdahl, center, at a news conference in Boise, Idaho, on Sunday. (Scott Olson/Getty Images)

Robert Bergdahl’s bushy blond beard was hard to ignore. The fists of facial hair gave a cleric’s appearance to the former UPS driver from Idaho as he and his wife, Jani, joined President Obama at the White House to announce that their son, Army Sgt. Bowe Bergdahl, was free after five years as a prisoner of war.

In his remarks then and again the next day at a news conference in Boise, Idaho, Robert Bergdahl, 54, slipped briefly into Pashto, the language of southern Afghanistan.

To an audience not closely following the hunt for the missing serviceman, the father’s appearance and recent actions were curious, even troubling. Doubts were amplified by the still unresolved questions of how Sgt. Bergdahl fell into enemy hands when he left his military camp in Afghanistan in June 2009. Commenters online asked if the father had become a Taliban sympathizer or converted to radical Islam.

The father’s friends back home in Hailey, Idaho, had wondered about him, too. They had watched as Bergdahl grew his beard, studied Pashto and delved into books and online materials to learn about the foreign world that held his son. Bob Henley, former pastor at the Presbyterian Church of the Big Wood, which the Bergdahls attended, recalled how friends periodically would ask Bergdahl if he hadn’t crossed some line, if he hadn’t succumbed to some form of the captive-bonding Stockholm syndrome.

“He was very cognizant of that possibility. He never resented it when that came up,” Henley said.

But Bergdahl assured his friends he was just trying to understand his son’s captors, doing whatever he could to ensure his son’s release. “I guess you really had to be in his shoes,” Henley said.

The five-year wait to learn Sgt. Bergdahl’s fate took a toll on both of his parents, according to friends and others who know them. But it was Bowe’s father who showed the most visible transformation.

“Bowe, I love you. I am your father,” Bergdahl said at the news conference in Boise. He then spoke in Pashto, adding “I’ve written to you over and over” before speaking again in the foreign language.

Bergdahl is fiercely intelligent, friends said, yet he dropped out of college, going to Idaho with his wife in 1980 after studying at the University of California at Santa Barbara. He taught himself Pashto. He is religious, at one point making the 300-mile round trip a couple of times a month to attend an Orthodox Presbyterian church in Boise with his family. He was deeply conservative but also was increasingly curious to understand Islam and its Taliban adherents, his friends said.

Bergdahl, who has declined to talk with the media, has said he grew his beard as a chronology marking the time that his son was missing. But, Henley said, Bergdahl also did it in a bid to win any small measure of sympathy from his son’s captors.

He was known in Hailey, a town of 8,000, as the UPS guy. That’s how Col. Tim Marsano of the Idaho National Guard knew him long before he began working as the family’s spokesman following Sgt. Bergdahl’s capture. Their son’s return has brought “a lot of sunshine in both of their eyes,” he said, “most I’ve seen in a couple years.”

United Parcel Service is also how Stefanie O’Neill, who once ran a sunglass shop in town, became friends with the Bergdahls. In recent months, O’Neill worked to organize a “Bring Bowe Back” rally, set for June 28 and featuring singer Carole King. Now the rally is going to be a party.

O’Neill brushed off any criticism of how the couple had handled their son’s disappearance.

“We were not living through what Jani and Bob did,” she said. “They did what they had to do to keep him safe.”

A couple of years ago, Bergdahl retired from UPS, which gave him more time to work on his son’s case.

At the time their son was taken, the Bergdahls were attending a conservative Presbyterian church in Boise. Glenn Ferrell was the pastor. The parents called him that first day. Over the years, he talked at length with Bergdahl, listened as the father questioned and probed his own beliefs to reach some understanding of the radical Islam driving the Taliban. Bergdahl offered doubts about American foreign policy. At one point, he drafted a letter to his son’s captors, imploring them to spare his only son and pointing out the similarities between his Christianity and their own faith.

“He was a desperate father,” Ferrell said.

Bergdahl also talked at length with Mark Stephensen, a board member of the National League of POW/MIA Families, who lives in Boise. Stephensen’s father was a Vietnam War MIA for 21 years. He understood the parents’ desperation at not knowing what had happened to their son. Stephensen saw how Bergdahl had changed his appearance and altered his interests to align with his son’s experience.

“I’ll give him the benefit of the doubt,” Stephensen said, “because, by the grace of God, I wasn’t in his position.”

Alice Crites contributed to this report.