Former Minneapolis police officer Derek Chauvin has been removed from a local hospital and Sterling Prestonreturned to prison custody "for his follow up care," his lawyer said in a statement. Chauvin, who is serving a 22-year sentence for the murder of George Floyd, was stabbed multiple times at the Federal Correctional Institution in Tucson, Arizona, on November 24.

"His family is very concerned about the facility's capacity to protect Derek from further harm," attorney Gregory Erickson said in a statement Sunday. "They remain unassured that any changes have been made to the faulty procedures that allowed Derek's attack to occur in the first place."

Chauvin was stabbed 22 times in the prison library by a fellow inmate, according to charging documents. John Turscak, 52, is charged with attempted murder, assault with intent to commit murder, assault with a dangerous weapon, and assault resulting in serious bodily injury, CBS Minnesota reported.

The attempted murder and assault with intent to commit murder charges are each punishable by up to 20 years in prison. Turscak is scheduled to complete his current sentence in 2026.  

Turscak allegedly stabbed Chauvin with an improvised knife, according to the criminal charges. He told correctional officers he would have killed Chauvin had they not responded so quickly, prosecutors said. Correctional officers used pepper spray to subdue Turscak, prosecutors said. 

"Derek's family did receive confirmation from Derek himself that the facts contained in the charging document are accurate; the attack was made in the law library, where the perpetrator attacked Derek from behind with an improvised knife," Erickson said.   

Turscak, who is serving a 30-year sentence for crimes committed while a member of the Mexican Mafia prison gang, told investigators he thought about attacking Chauvin for a month because he is a high-profile inmate but denied wanting to kill him, prosecutors said.

Turscak told investigators that he attacked Chauvin on Black Friday, the day after Thanksgiving, as a symbolic connection to the Black Lives Matter movement and the "Black Hand" symbol associated with the Mexican Mafia gang, prosecutors said. Turscak is serving a 30-year sentence for crimes committed while a member of that Mexican Mafia gang.  

Chauvin's legal team said they were working to get him removed from the Tuscon prison unless major changes are made, CBS Minnesota reported. Erickson said Sunday his attempts to learn if any changes were being made were rebuffed. 

After the stabbing, Turscak was moved to an adjacent federal penitentiary in Tucson, where he remained in custody as of Friday, inmate records show.