Charges have been filed against an inmate accused of stabbing Derek Chauvin more than 20 times in a federal prison last week, court documents show.

John Turscak, 52, faces federal charges of attempted murder, assault with intent to commit murder, assault with a dangerous weapon and assault resulting in serious bodily injury in connection with the Nov. 24 attack at the federal prison in Tucson, Arizona.

Turscak, a former member of the Mexican Mafia, is serving a 30-year prison sentence for crimes committed while he was acting as an FBI informant, according to the Los Angeles Times. He was sentenced in 2001.

According to a criminal complaint, Turscak and Chauvin were together in the prison’s law library when Turscak allegedly stabbed Chauvin “approximately 22 times” with an improvised weapon. Turscak continued the attack until corrections officers used pepper spray on him, and he allegedly stated he would have killed Chauvin had they not intervened.

Turscak told FBI agents that he had been thinking about attacking Chauvin for about a month because of Chauvin’s notoriety but denied wanting to kill him, the complaint says. The assault happened on Black Friday, a day that Turscak said was connected to the Black Lives Matter movement and the “Black Hand” symbol associated with the Mexican Mafia.

Chauvin suffered serious injuries in the attack and was in stable condition as of Saturday.

Chauvin — the white former Minneapolis police officer who murdered George Floyd, a Black man — is serving a 20-year federal prison sentence for violating Floyd’s civil rights.

Days before the attack occurred, the U.S. Supreme Court denied Chauvin’s appeal of his state conviction of second-degree murder.

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