(NewsNation) — A Utah woman charged with killing her husband by poisoning him is seeking to get the charges thrown out over what her lawyers claim is prosecutorial misconduct.

Defense attorneys for Kouri Richins filed a motion to dismiss Wednesday, arguing that prosecutors erred when they characterized a jailhouse letter written to family as “witness tampering,” even though Richins has not been charged with such a crime.

Ritchins is accused of killing her husband, Eric, by giving him a lethal dose of fentanyl. While being held in jail, she wrote a letter asking her mother and brother to tell police that her husband abused drugs and obtained pain pills and fentanyl from Mexico.

Prosecutors contend the letter amounts to witness tampering and previously asked a judge to prevent Richins from further contacting her mother and brother. The defense team claims the letter is being misconstrued.

Richins’ lawyers previously asked the state to sanction the prosecution for posting the letter on the public court document, which the defense claimed was a violation of a gag order.

Her latest motion claims the prosecution’s characterization of the letter as witness tampering would sway potential jurors, “such that a fair trial in this case is no longer possible,” Court TV reported.

Defense attorneys also claim the letter was obtained in an illegal search, KTSU-TV reported. Prosecutors say Summit County Jail personnel found it inside a book, but Richins’ lawyers contend it was in an envelope marked “Skye Lazaro (Attorney Privilege)” and had no crease marks.

If the court denies the motion to dismiss, attorneys have asked the case be moved to a different county and that a judge bar the handwritten letter from being allowed at trial.