BATON ROUGE, La. (BRPROUD) — The mother of a two-year-old child who died from a fentanyl overdose over the summer pled not guilty to a second-degree murder charge in court Tuesday.

Whitney Ard, 28, was arrested by deputies in August on a negligent homicide charge after two-year-old Mitchell Robinson was declared dead at a hospital in June. According to the East Baton Rouge Sheriff’s Office, Robinson’s sibling said he “ate mom’s pills.”

The East Baton Rouge Coroner’s Office said Robinson’s death was due to “acute fentanyl toxicity.”

The Louisiana Department of Children and Family Services (DCFS) launched an internal review into the case, saying they were making policy changes and working with the Office of Inspector General.

Ard was formally charged with second-degree murder at the tail end of September.