Gen. Robert B. Abrams, Commander, U.S. Army Forces Command, on May 5, 2016. (Mark C. Olsen/U.S. National Guard)

FORT BRAGG, N.C. – The four-star Army general who sent accused deserter Sgt. Bowe Bergdahl’s case to a felony-level, general court-martial will be required to testify Wednesday about accusations that he destroyed letters related to the case, a military judge has ruled.

Bergdahl’s lawyers have asked Col. Jeffery R. Nance to remove Gen. Robert Abrams, the chief of Army Forces Command, from his role as convening authority after he admitted he sent some 100 letters that he received from the public about the case to be burned.

Nance’s decision came Monday during a pre-trial hearing in which he also determined Berghdahl’s attempt to join the French Foreign Legion and his time on a weapons range prior to enlisting cannot be used in his court-martial as evidence of his pursuits of adventure.

The hearing will continue Tuesday with discussion about comments made by Sen. John McCain, R-Ariz., that Bergdahl’s attorneys have argued impede their client’s right to a fair trial.

Last year, the Army charged Bergdahl, 30, with desertion and misbehavior before the enemy after he spent five years in Taliban captivity. The more serious misbehavior charge could send the soldier to prison for the rest of his life. His court-martial is scheduled for February, but Nance said Monday it could be pushed back to a later date.

Bergdahl’s attorneys argued the letters that Abrams received could have been relevant during sentencing and could have contained information they had the right to view as they prepare for the court-martial.

The letters came to light earlier this month when defense attorneys interviewed Abrams, who admitted receiving, “briefly scanning” and placing the letters in a burn bag. The letters were supportive and critical of Bergdahl, according to court documents.

In an affidavit submitted Friday to the court, Abrams wrote he received “the vast majority” of the correspondence after he referred the case to a general court-martial in December. Abrams added none of the letters were from “anyone in the chain of command, the Department of Defense, or the United States government,” and he did not consider them “in making any decisions regarding the case.”

Bergdahl’s lawyers have been critical of Abrams’ decision to send the case to a general court-martial after the officer who oversaw a preliminary hearing in September 2015 recommended the case be sent to a misdemeanor-level court and said the soldier should not be imprisoned.

Eugene R. Fidell, Bergdahl’s chief civilian attorney, questioned Abrams’ claim he was not influenced by the letters, especially the ones containing negative opinions of his client.

“If we don’t know what sort of nastygrams (Abrams) is reading, why do we have to take his word that it’s water off his back?” Fidell said.

While prosecutors argued it was not necessary for Abrams to testify, Nance said he had “some questions” about the letters. Nance will allow the general to provide his sworn testimony by telephone because he is traveling on official business.

Nance said he did not expect to decide Wednesday whether he would remove Abrams from the case.

Nance did decide Monday that Bergdahl’s attempt to join the French Foreign Legion and his time spent working on fishing boats and on a weapons range in the years before he enlisted in 2006 were not relevant to the case.

Nance said introducing those acts as evidence, which prosecutors wanted to do, would waste time during a court-martial already expected to last up to two weeks.

Maj. Jerrod Fussnecker, an Army prosecutor, argued Monday that those events showed Bergdahl’s intent to constantly “seek adventure,” saying the soldier retained the same mindset to “show he was a super soldier … like Jason Bourne” when he walked off Observation Post Mest in eastern Afghanistan in 2009. Bergdahl was captured by Taliban fighters shortly after he left the post.

Nance called the prosecutors’ argument a “big logical leap” and added they do not need to prove his motive for leaving.

“You just have to prove he went absent without authority,” the judge said.

Bergdahl has admitted to Army investigators that he willingly left the post before he was captured, but he said he did not intend to desert the Army. Instead, he said he wanted to cause a disturbance that would place him in front of military brass to file complaints about his chain of command.

Tuesday morning, Nance will hear arguments concerning the defense’s motion early this month to dismiss the charges against Bergdahl because of comments McCain made to reporters in October. McCain said the Senate Armed Services Committee, of which he is the chairman, would hold a hearing if Bergdahl is not punished.

That comment, Bergdahl’s attorneys wrote, inappropriately meddled in the ongoing case and could have impacted decisions made by Army leaders, including Abrams’ decision to send the case to the felony-level court.

Bergdahl remains on active duty in a desk job at Joint Base San Antonio in Texas. He was arraigned on charges of “misbehavior before the enemy by endangering the safety of a command, unit or place” and “desertion with intent to shirk important or hazardous duty” in December, but he has yet to enter a plea. He was freed in May 2014 after spending five years in the captivity of the Taliban-linked Haqqani Network in Pakistan in a controversial exchange for five senior Taliban leaders who had been held at the detention facility at Guantanamo Bay in Cuba.

Dickstein.corey@stripes.com Twitter: @CDicksteinDC