A onetime Los Angeles street gang member serving time in an Arizona federal prison was charged Friday with attempted murder on allegations that he stabbed fellow prisoner Derek Chauvin, the former Minneapolis police officer who murdered George Floyd 3½ years ago.

John Turscak, 52, was charged in U.S. District Court with attempted murder, assault with intent to commit murder, assault with a dangerous weapon and assault resulting in serious bodily injury stemming from the Nov. 24 attack in the Tucson prison's law library.

Turscak stabbed Chauvin 22 times with an improvised knife, the charges said.

After Turscak was subdued by corrections officers, he said he had been thinking about attacking Chauvin because of the fired police officer's notoriety from the killing of Floyd in May 2020.

"Turscak stated he saw an opportunity to assault [Chauvin] in the law library. .... Turscak stated that his attack of [Chauvin] on Black Friday was symbolic of the Black Lives Matter movement and the 'Black Hand' symbol associated with the Mexican Mafia crime organization," according to the charging document.

He also told corrections officers that "he would have killed [Chauvin] had they not responded so quickly," the charges continued.

Court records do not list an attorney for Turscak, nor do they show any scheduled court hearings.

The U.S. Bureau of Prisons said shortly after the stabbing that Chauvin, 47, was seriously wounded and in stable condition. The agency has otherwise refused to release any details about his physical well being.

Chauvin's mother and one of his attorneys have criticized prison officials for keeping them in the dark about last week's stabbing. In a Facebook post Friday, his mother, Carolyn Pawlenty, noted that it had been one week and that she had yet to be provided any information from the FBI or Bureau of Prisons, other than "he is in stable condition and it is under investigation."

"It is time for you to tell me....who did this, where were the guards? Where is the video showing what happened?? How could you let this happen? I demand answers!!"

Chauvin has been serving a 21-year federal sentence for violating Floyd's civil rights and a 22 ½-year state sentence for second-degree murder. He's due to be released from prison in 2038, according to Bureau of Prison records.

Minnesota Attorney General Keith Ellison, whose office led the prosecution, "is saddened and concerned by the attack on Derek Chauvin, and he believes that Chauvin, like all incarcerated people, should be able to serve his sentence in peace," according to a statement from Brian Evans, a spokesman for the attorney general's office.

Floyd, who was Black, died while pinned under the knee of Chauvin, who is white, at the corner of Chicago Avenue and 38th Street in south Minneapolis. Floyd's death ignited days of protests and at times deadly riots.

Turscak was sentenced in November 2001 to 30 years in prison for committing numerous crimes while acting as an undercover informant for the FBI in the Los Angeles area.

According to the Los Angeles Times, Turscak became an informant in an investigation that led to indictments of more than 40 suspected Mexican Mafia members and associates. However, midway through the undercover operation, the Times reported, prosecutors dropped him as an informer after he admitted dealing drugs, extorting money and authorizing assaults while on the government payroll.

He pleaded guilty to racketeering and conspiring to kill a rival in the prison-based gang, the Times noted.

Turscak was scheduled for release in 2026, according to the Bureau of Prisons. In a 2005 court filing, he requested a transfer from the federal penitentiary in Atlanta by claiming his life was in "imminent danger" from fellow inmates "as a result of my past cooperation with the government in the Mexican Mafia investigation, and assistance to … authorities here at the prison."

In a 2008 book about the Mexican Mafia, Chris Blatchford , a former reporter for KTTV-TV and KCBS-TV in Los Angeles, wrote that Turscak was not Mexican but the son of parents from the former Czechoslovakia. He was collecting $2,000 a month working for the FBI, the book noted.

Turscak, whose street name was "Stranger," joined a gang at age 13 and was involved in shootings. His arrest for robbery at age 16 was part of a murder plot that police foiled, Blatchford's book revealed.

During Turscak's years in prison for robbery and false imprisonment, went one account in Blatchford's "The Black Hand: The Story of Rene 'Boxer' Enriquez and His Life in the Mexican Mafia," Turscak carried out roughly 10 stabbings, most at the direction of the in-prison La Erne gang.

Chauvin is the latest high-profile inmate to be attacked at a federal prison. In July, convicted sex offender and former Michigan State University doctor Larry Nassar was stabbed repeatedly at a facility in Florida.

In 2018, former Boston mob boss James "Whitey" Bulger was killed shortly after being transferred to a federal prison in West Virginia. A Justice Department report late last year excoriated the prison's management for Bulger's death.

A series of Associated Press reports in 2022 found that the Bureau of Prisons has long been plagued by staffing shortages, chronic violence, inmate deaths and sexual abuse of prisoners by staff.

Star Tribune staff writer Abby Simons contributed to this story.

An earlier version of this story misstated where Chris Blatchford worked when he researched the book "The Black Hand: The Story of Rene 'Boxer' Enriquez and His Life in the Mexican Mafia."