Derek Chauvin's family is angry they learned from the media their imprisoned son was stabbed and not from prison officials.

Carolyn Pawlenty, the mother of the cop who murdered George Floyd, told Alpha News, "How the hell do these news agencies know and his own mother doesn't even know?" She adds the prison had an emergency contact number -- her number -- but no one called.

She went on ... “I can’t even think what to say. I haven’t been to bed and made a path in my kitchen and living room floor by pacing."

Chauvin’s attorney, Bill Mohrman, says he got involved and tried calling the prison for information but hasn't heard back.

And another Chauvin lawyer, Gregory M. Erickson, slammed prison officials for its radio silence ... “It appears to be indicative of a poorly run facility and indicates how Derek’s assault was allowed to happen.”

Erickson added, “How the family members who are in charge of Derek’s decisions regarding his personal medical care and his emergency contact were not informed after his stabbing further indicates the institution’s poor procedures and lack of institutional control.”

As we reported ... Chauvin was stabbed in the federal prison in Arizona where he is currently serving a nearly 21-year sentence after pleading guilty to a federal charge of violating Floyd's civil rights.

Chauvin is in stable condition after he was assaulted Friday at the Federal Correctional Institution in Tucson. The stabbing was reportedly carried out by another inmate.

Prison doctors performed "life-saving" measures on Chauvin. There have been no updates on his condition.