An inmate was charged on Friday with attempted murder and other offences following the stabbing of Derek Chauvin, the former Minneapolis police officer convicted in the death of George Floyd, the US Justice Department said in a statement.

The complaint charges John Turscak, 52, with stabbing Chauvin about 22 times “with an improvised knife” on Nov 24 while incarcerated at Federal Correctional Institution Tucson, prosecutors said.

Turscak was charged with attempted murder, assault with intent to commit murder, assault with a dangerous weapon, and assault resulting in serious bodily injury, according to prosecutors.

Turscak is serving a 30-year sentence over crimes that were committed when he was a member of the Mexican Mafia gang.

The investigation in the case was conducted by the FBI.

“Turscak stated that his attack of D.C. (Derek Chauvin) on Black Friday was symbolic with the Black Lives Matter movement and the Mexican Mafia criminal organization,” the complaint said.

Turscak also told investigators he had been thinking of assaulting the former police officer for about a month due to his high-profile status, according to prosecutors.

An attorney for Turscak was not listed in court records.

Attempted murder and assault with intent to commit murder violations each carry maximum penalties of 20 years incarceration, while assault with a dangerous weapon and assault resulting in serious bodily injury each carry maximum penalties of 10 years.

Chauvin was expected to survive, the Minnesota Attorney General’s office said after the stabbing.

Chauvin is serving a 21-year sentence for violating Floyd’s civil rights and a concurrent 22.5 years for murder on his conviction in Minnesota state court.

Floyd’s death in 2020 unleashed protests worldwide against police brutality and racism after Chauvin, who is white, knelt on the neck of the handcuffed Black man for more than eight minutes in a murder caught on cellphone video.