MINNEAPOLIS (WCCO) – A 42-year-old man is accused of fatally beating corrections officer Joe Gomm with a hammer earlier this month at the Stillwater Correctional Facility, according to charges filed Thursday in Washington County Court.

Edward Johnson has been charged with second-degree murder and second-degree assault with a dangerous weapon in connection with the July 18 incident.

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According to the charges, corrections officers and medical personnel were called at about 1:34 p.m. on July 18 to a report of a staff assault in the M Shop at the Stillwater Correctional Facility. When authorities arrived, they discovered Gomm laying on the floor of the shop with substantial injuries to his head and face.

He was transported to Regions Hospital, where he was pronounced dead. The Ramsey County Medical Examiner’s Office determined Gomm died of multiple blunt force injuries to his head and two puncture wounds to his chest.

The complaint states the BCA, Bayport police and Washington County Sheriff’s Office responded to the prison to investigate. More than 50 witnesses were interviewed, and it was determined Gomm was attacked by Johnson, an inmate serving a sentence for murdering his former girlfriend in 2002.

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The complaint states a shop foreman at the prison told investigators he was approached by an inmate who said Officer Gomm needed help. The foreman went into the shop and saw Johnson beating Gomm in the head with a hammer. The foreman ordered him to stop, and called for help on his portable radio. The foreman then said Johnson stopped attacking Gomm and approached him with the hammer, swinging it at him. The foreman, fearing for his life, retreated to a nearby stairwell.

The complaint states Johnson then shut the door leading to the stairwell and barricaded it.

According to the complaint, several inmates told investigators Johnson was running around the M Shop without a shirt on. Johnson was telling them, “You guys are fine,” meaning he wouldn’t attack them. Several responding correctional officers located Johnson with his hands up, and he said he was surrendering. He was taken into custody. Several inmates told investigators that inmates often remove their shirts if they are involved in a fight or assault.

The complaint states investigators learned a hammer was checked out to Johnson when he reported for work that afternoon. A bloody hammer was found not far from where Gomm was found. Investigators also found two knives, at least one of which was used to stab Gomm.

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Johnson remains imprisoned for the previous murder conviction of his former girlfriend.