Derek Chauvin, the former Minneapolis police officer convicted of George Floyd’s murder, was seriously injured in a prison stabbing Friday, a law enforcement source with knowledge of the incident said.

Chauvin was being held at the medium-security Federal Correctional Institution, Tucson, when the incident took place, the source said.

The Federal Bureau of Prisons would not confirm the victim of an attack at that facility on Friday is Derek Chauvin, but it offered other details in a statement, including that the victim was hospitalized.

The assault took place about 12:30 p.m., the bureau of prisons said, and “responding employees initiated life-saving measures for one incarcerated individual.”

“Responding employees isolated and contained the incident and at no time was the public in danger,” the bureau said.

The patient’s condition was not immediately available.

The bureau of prisons said in notified the FBI of the attack, though it did not provide further details about why it did so.

An FBI spokesperson based in Phoenix said by email Friday night that the FBI was “aware of an assault” at the Federal Correctional Institute in Tucson. Any more information would have to come from the bureau of prisons, the spokesperson said.

Minnesota Attorney General Keith Ellison said in a statement that he was “saddened” by the incident.

“I am sad to hear that Derek Chauvin was the target of violence,” Ellison said. “He was duly convicted of his crimes and, like any incarcerated individual, he should be able to serve his sentence without fear of retaliation or violence.”

Chauvin, Tou Thao, J. Alexander Kueng and Thomas Lane — on-duty Minneapolis police officers when they confronted Floyd on May 25, 2020, based on a complaint of a fake $20 bill passed at a convenience store — have all been convicted in both state and federal courts for crimes leading to Floyd’s death.

Chauvin, who knelt on Floyd’s neck for 9½ minutes while Floyd said he couldn’t breathe and went limp, is simultaneously serving a 21-year federal sentence for violating Floyd’s civil rights and a 22½-year state sentence for second-degree murder.