A 22-year-old man serving a four-year sentence for burglary was killed in a Maryland prison Tuesday night, and state police investigators are working to identify those responsible.

Police said an officer at the Maryland Correctional Institution, Hagerstown was getting ready to count inmates about 10:30 p.m. when he saw an inmate bleeding. The inmate – later identified at 22-year-old Deavel M. Johnson – soon collapsed with what appeared to be at least one wound on his upper body, police said. He was treated at the prison and then transported to the hospital, where he was later pronounced dead, police said.

Police said the medical examiner would determine precisely how Johnson died, though they called the incident an “apparent murder.” Other inmates were in the dorm area when the officer spotted Johnson bleeding, but police have not identified any suspects, authorities said.

Police said Johnson was serving a four-year sentence for burglary and had been incarcerated since 2011.