SMYRNA, Del. (CBS) — Some union workers at the prison where the deadly standoff took place previously complained about violence among the inmates.

CBS 3’s Cleve Bryan reports the Correctional Officers Association of Delaware say a staffing crisis and new requirements to allow inmates more time out of their cells left Sgt. Steven Floyd and other prison staff vulnerable at James T. Vaughn Correctional Center. Geoff Klopp, the union’s president, says Floyd’s death was preventable.

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In the months before the riot, the union was sharing stories of more and more assaults against officers.

“The inmate immediately reached for his ankle and pulled out a home-made metal weapon out of his sock that was shaped like a knife,” Klopp said about an incident that occurred over a week ago when an officer opened a cell.

Officers say inmates have been faking emergencies to test the staff’s readiness for a riot.

“There have been recent dry runs at the facility where the inmates are testing and prodding to see where weak points are and we still have concerns among the facilities,” Klopp said.

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The union says not only are facilities understaffed, poor pay has also made it hard to keep officers experiences at controlling the prison population.

During a small protest outside the prison, former Vaughn inmate James Green echoed the same concern about inexperienced officers.

“This was building up, it just came to a point where it was unity. Unity says it all,” Green said.

He continued, “I mean, the end result of the officer dying, I mean I show remorse and I send my condolences.”

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A candlelight vigil will be held in Smyrna on Friday night to honor Floyd.