SIOUX FALLS, S.D. (AP) - Two inmates accused in an attack that left a South Dakota prison guard hospitalized have pleaded not guilty.

Twenty-eight-year-old Carlos Green and 24-year-old Garrett Dumarce made their initial court appearances Thursday in Sioux Falls.

Authorities say Cpl. Zane Mathis was hospitalized April 20 with a broken jaw and facial cuts after he was punched several times in the head.

Green is charged with aggravated assault of a corrections employee. He faces life in prison.

Dumarce is charged with aiding, abetting or advising aggravated assault against a corrections employee. He could face up to 50 years in prison.

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