A former Rapid City dentist already facing sentencing on federal charges of criminal contempt and conspiracy to distribute misbranded medical devices could now have more legal troubles.

The prosecutor in the Larry Lytle case has sent a letter to the U-S Probation Office outlining a 24-page letter Lytle sent to him and says Lytle may have committed more felonies with that letter.

In the letter, Lytle threatens to sue the prosecutor for $10 million and have him thrown in prison for ten years unless his prosecution is terminated.

The prosecutor's letter says Lytle's threats are a familiar part of the "sovereign citizen" movement.

Lytle's letter filed with the court on March 29th closes by saying "You have been warned. Proceed after warning at your peril. Govern yourself accordingly. Speak now or forever hold your peace."

Lytle is set to be sentenced on April 20th in federal court after admitting to marketing and selling Q-Lasers that he labeled for veterinary use as an effective treatment for humans for more than 200 medical conditions.