Officials declined to explain circumstances of assault.
Three federal prisoners have been charged with ambushing two corrections officers at the Sherburne County jail.
Indicted Tuesday in federal court in St. Paul were Ira L. Goodwin, Michael S. Luedtke and Edward M. Robinson for their roles in the Feb. 8 attack.
Prosecutors say Jesse P. Kipka was assaulted with a chair and hit on the head with his own pepper spray can. Jesse J. Overlie was struck with a chair. Kipka suffered a concussion, and both were “extensively bruised,” U.S. attorney’s office spokeswoman Jeanne Cooney said.
The Sheriff’s Office declined to comment. Cooney said the public case file against the inmates did not address why the attack occurred.
Robinson, 28, was being held while his trial continues in an arson and double murder on the Red Lake Indian Reservation in northern Minnesota. He’s one of four accused of stealing money and drugs from a reservation couple, stabbing them and leaving their bodies to burn on New Year’s Day, 2011.
Goodwin, 26, an admitted member of the Native Mob gang, was awaiting sentencing in a conspiracy trial involving fellow gang members.
Prosecutors describe the Native Mob as a disciplined criminal organization with more than 200 members operating in Minnesota, Wisconsin and elsewhere.
Luedtke, 25, was awaiting transfer to a federal prison to begin serving a 25-year sentence after admitting to holding up three Twin Cities sandwich shops in December 2011.
All three remain in the Sherburne County jail, which rents most of its bed space to the federal government.