Originally Published: 02 OCT 23 12:13 ET

By Alta Spells and Eric Levenson, CNN

(CNN) — A corrections officer at a south Georgia prison was killed Sunday after an inmate allegedly attacked him “from behind with a homemade weapon,” the state department of corrections announced in a news release.

Robert Clark, 42, was escorting two offenders, Layton Lester and Marko Willingham, from the dining hall at Smith State Prison when Lester assaulted him from behind, the department said. Willingham stepped in to help Clark during the attack and was also injured.

Clark and Willingham were taken to the hospital. Clark, who began working with the Georgia Department of Corrections in April, died of his injuries, while Willingham remains hospitalized with non-life-threatening injuries.

“The entire GDC team is mourning the loss of one of our own and we collectively express our deepest condolences to Officer Clark’s family and friends,” commissioner Tyrone Oliver said in a statement. “We will support them as they navigate this tragedy over the coming days, weeks and months.”

Lester is expected to be charged in the fatal assault of Clark and in the assault of Willingham, the department said.

He was previously convicted of a 2007 murder and armed robbery and has been incarcerated since 2010, according to online prison records.

The killing is part of a troubling series of incidents at Smith State Prison in Glennville, about 50 miles west of Savannah.

In February, the prison’s warden Brian Adams was fired and arrested on charges of conspiracy to violate the Racketeer Influenced and Corrupt Organizations Act, bribery, false statements and violation of oath by a public officer, according to the Georgia Bureau of Investigation.

The case stemmed from an investigation into the killing of an 88-year-old local man, who was shot to death in his home in January 2021. Authorities have charged a Smith State Prison inmate, Nathan Weekes, with conspiracy to commit murder and RICO violations, and the investigation showed he was involved in smuggling contraband inside the prison, according to the bureau.

An investigation by The Atlanta Journal-Constitution published two weeks ago uncovered more than 425 cases in which Georgia Department of Corrections employees have been arrested since 2018 for crimes on the job, most of which involved contraband.