BAYPORT, Minn. (AP) — An inmate used a weapon to kill an officer at a Minnesota state prison, in the first death on record of an on-duty prison guard in the state, corrections officials said.

State Corrections Commissioner Tom Roy declined to describe the weapon used to kill Officer Joseph Gomm Wednesday afternoon at the state's flagship prison in Stillwater. Gomm was killed in Stillwater's industry building, which houses a welding shop and carpentry programs, Roy said at a news conference Wednesday.

The inmate, Edward Muhammad Johnson, 42, was convicted of second-degree homicide in 2003 and was serving a nearly 29-year sentence. He has not been charged in Gomm's death. Washington County Attorney Pete Orput said Thursday that Johnson has been moved to the state's maximum-security facility in Oak Park Heights and was in segregation.

Officials have said Johnson acted alone in the attack on Gomm, which is under investigation.

Gomm, like most guards, was armed only with pepper spray and a radio, Roy said. Guns are typically only used by officers stationed in watch towers and assigned to crisis response teams.

More than 1,600 inmates are housed at the 104-year-old Stillwater prison, and about a third of them are serving time for homicide.

The guard's on-duty killing "is the first in the state, as far as we can verify through our records," according to Department of Corrections spokeswoman Sarah Fitzgerald.

"The corrections family is reeling from this incident," Roy said. "We are not accustomed to losing staff."

Rogers police Chief Jeff Beahen, president of the Minnesota Law Enforcement Memorial Association, told the Star Tribune that Gomm's death was a reminder that unarmed prison guards can face more risks than armed police officers.

"This really shows how dangerous the correctional officer job can be," Beahen said.

Beahen has offered Gomm's family a 'line-of-duty' funeral, a procession that typically includes bagpipes and attracts hundreds of officers from across the state and beyond.