Disgraced former Congressman Anthony Weiner instructed a 15-year-old girl to undress and touch herself, then watched as she did so via Skype, according to a court filing submitted by the federal government on Wednesday.

"With full knowledge that he was communicating with a real 15-year-old girl, the defendant asked her to engage in sexually explicit conduct via Skype and Snapchat, where her body was on display, and where she was asked to sexually perform for him," read the federal government's memo, submitted ahead of Weiner's sentencing next week.

Noting that the offense was "far from mere 'sexting,'" prosecutors Amanda Kramer and Stephanie Lake called on the judge to send Weiner to prison for 21 to 27 months. The memo also cast doubt on Weiner's current claims of rehabilitation, noting that his "demonstrated history of professed, yet failed, reform make it difficult to rely on his present claim of self-awareness and transformation."

The sentencing comes after Weiner pleaded guilty this spring to transmitting sexual material to a minor, and agreed not to appeal any sentence shorter than 27 months. Weiner had been under investigation by the FBI since last year—a probe that intersected with the FBI's investigation of Hillary Clinton during the presidential election, ultimately leading to unforeseen consequences.

Last week, Weiner's lawyers filed their own sentencing memorandum, which asked the judge not to put the ex-lawmaker in jail, noting that he was a "weak man." They argued that their client was the victim of a honeypot scheme, and that he is not sexually interested in minors. The also pointed out that the victim admitted to targeting Weiner to change the course of the election, which they argued should factor into the sentencing decision.

"This crime is a product of a sickness," the memo from Weiner's lawyers read. "No one can dispute that Anthony’s operatic self-destruction, of which the instant case has been but the final act, was born of deep sickness." The court filing also flagged Weiner's "remarkable career in public service," as well as his "troubled childhood," as explanations for his crime.

On Wednesday, prosecutors acknowledged that his fall from grace was, indeed, sad, but urged the judge to put Weiner behind bars all the same.

"Although the defendant's self-destructive path from United State Congressman to felon is indusputably sad, his crime is serious and his demonstrated need for deterrence is real," the prosecutors wrote.

A Manhattan judge is scheduled to sentence Weiner on Monday.