Attorneys for Army Sgt. Bowe Bergdahl sent Donald Trump a letter on Saturday in an effort to determine if a deposition from him will be necessary, according to BuzzFeed News. The lawyers say Trump’s damaging statements about the disgraced soldier will prevent Bergdahl from having a fair trial. They told Trump on Saturday that they need to speak with him as “soon as possible” about his statements.

Trump has called for the ex-soldier’s execution, called him a ‘”no-good” and “dirty rotten” traitor. Just to name a few.  Bergdahl’s attorneys are determining whether to call Trump as a witness during Bergdahl’s upcoming court-martial. They claim that Trump’s disparaging statements could influence the jury in the ex-soldier’s criminal case.

The former Taliban prisoner is expected to go on trial later this year, and a Trump appearance would come at the heart of the presidential campaign season.

“This is the lowest kind of demagoguery,” Bergdahl’s attorney Eugene Fidell told BuzzFeed. “Mr. Trump’s comments are contemptible and un-American. They are a call for mob justice.”

Berghdal was released from a Taliban prison in 2014 as part of a prisoner exchange for five Talibans members who were being held at Guantanamo Bay. In March, he was charged with desertion and endangering the safety of a command under the Uniform Code of Military Justice.

“The statements could have the impact of potentially inflaming or chilling the jury,” Floyd Abrams, a well-known constitutional attorney told LawNewz.com, “But I can not conjure up any basis for having Mr. Trump testify.”

[h/t Buzz Feed]