“He wouldn’t drink beer or eat barbecue and hang out with the other 20-year-olds,” Cody Full, another member of Sergeant Bergdahl’s platoon, said in an interview on Monday also arranged by Republican strategists. “He was always in his bunk. He ordered Rosetta Stone for all the languages there, learning Dari and Arabic and Pashto.”

The soldiers began a frantic search for Sergeant Bergdahl using Predator drones, Apache attack helicopters and military tracking dogs. The most intense search operation, leaked war reports show, wound down after eight days — well before the deaths of six soldiers on patrols in Paktika Province in late August and early September. But, complicating matters, some soldiers contend they were effectively searching for 90 days because of clear orders: If they heard rumors from locals that Sergeant Bergdahl might be nearby, they should patrol the area.

Mr. Full, then a specialist in the platoon, said he and other platoon members grew increasingly bitter at the time they were spending looking for Sergeant Bergdahl. “He had sent all his belongings home — his computer, personal items,” said Mr. Full, now 25. He said Sergeant Bergdahl used to gaze at the mountains around them and say he wondered if he could get to China from there. Other platoon members said that Sergeant Bergdahl wrote Jason Bourne-type novels in which he inserted himself as the lead character.

The anger toward Sergeant Bergdahl increased exponentially after Sept. 4, when they learned that two members of Third Platoon, which routinely went on tandem missions with Second Platoon and who they believed were also searching for Sergeant Bergdahl, had been killed in an ambush. Pfc. Matthew Martinek and Lt. Darryn Andrews, both of them friends of Mr. Cornelison, died in the ambush. A Defense Department official said it was unclear whether the two men were killed directly because of the search for Sergeant Bergdahl.

Some soldiers have also contended that the Taliban, knowing the units were out searching extensively for Sergeant Bergdahl, chose July 4, 2009, to attack another combat outpost, which was nearly overrun and several soldiers were killed. But American military officers said they saw no evidence that the Taliban started the attack on the outpost because they thought everyone would be out searching for Sergeant Bergdahl.

A second former senior military officer, who also was briefed on the Bergdahl investigation, said there was no direct evidence that diversion of surveillance aircraft or troops to search for Sergeant Bergdahl encouraged the Taliban attacks, or left other American troops vulnerable. “This was a dangerous region in Afghanistan in the middle of the ‘fighting season,’ ” the officer said in an email, adding that although the search “could have created some opportunities for the enemy,” it is “difficult to establish a direct cause and effect.”

A review of the database of casualties in the Afghan war suggests that Sergeant Bergdahl’s critics appear to be blaming him for every American soldier killed in Paktika Province in the four-month period that followed his disappearance.