MITCHELL, SD (Mitchell Now) — A grand jury has returned indictments against a South Dakota inmate and a former state employee following a fatal overdose inside the South Dakota State Penitentiary.

Attorney General Marty Jackley announced that Natalie Krause, a former nurse at the penitentiary, is accused of bringing K2 — a synthetic form of marijuana — into the prison. Prosecutors allege Krause gave the drug to inmate Cole Waters.

According to investigators, Waters then provided the substance to fellow inmate Travis Long Fox, who died from an overdose last month.

“South Dakota has my commitment as Attorney General that when there’s unlawful criminal activity in the penitentiary, we will not only investigate it with a thorough investigation, we will bring the charges necessary to hold individuals accountable and keep those drugs out of the penitentiary,” Jackley said.

If convicted, Waters faces up to 170 additional years in prison. Krause faces a potential maximum sentence of 75 years.

Jackley also said the investigation into drug activity at the penitentiary is ongoing. Several additional cases are still under review, with more charges expected to be filed in the coming months.