A former Rockdale County Sheriff's Office sergeant under investigation on suspicions that he stole guns from his agency's evidence unit now faces 43 counts of felony theft.

Dan Lang, 37, stole more than $40,000 in cash in addition to the guns, the GBI said Thursday. The bureau launched its investigation April 10, after a sheriffs supervisor informed agents that Lang may have marked the firearms as destroyed then sold them for cash at pawn shops.

Lang was a supervisor with the unit. Internal auditors discovered the evidence was missing during an unannounced check in late 2017, agency records state.

Lang was transferred to the agency's jail, where admitted to falsifying records in the March 12 death of inmate Shali Tilson, 22, who was under his supervision. Jailers were supposed to perform 15 minute checks on Tilson, who was diagnosed with schizophrenia and bipolar disorder, but instead ignored him for more than three hours before he was found dead, a separate internal investigation found. Tilson died at the jail of blood clots in his lungs caused by dehydration.

Lang was demoted from sergeant to corporal March 26 and given two days suspension for the evidence unit lapses. He resigned April 9 citing “family considerations.”

Tilson’s death sparked community protest.

Lang turned himself in Thursday to the Rockdale County Jail without incident, according to a GBI spokeswoman. He faces one count of violating his oath of office in addition to the theft charges.