Derek Chauvin -- the cop convicted of murdering George Floyd -- was stabbed 22 times in a brutal attack behind bars ... and the inmate responsible says he wanted Chauvin dead.
Federal prosecutors announced Friday inmate John Turscak was charged with attempted murder in the prison stabbing. Using an improvised knife, Turscak attacked Chauvin on November 24 in the law library at the Federal Correctional Institution in Tucson, Arizona.
According to prosecutors, 52-year-old Turscak told corrections officers he would've killed Chauvin if they hadn't intervened.
As we reported, Chauvin's family had been left in the dark in the days following the attack ... pissed prison officials hadn't offered them more info other than the fact Chauvin was in critical but stable condition.
Chauvin was convicted of Floyd's murder and sentenced to more than 22 years in prison. He was also given a 20-year term on a separate federal charge of violating Floyd's civil rights ... which is what he's serving in Arizona.
BTW ... November 24, the day of the attack, was also Black Friday -- and Turscak told agents he chose the date as a connection to the Black Lives Matter movement and the "Black Hand" symbol associated with the Mexican Mafia gang.