Nick and Aaron Carter's late sister, Bobbie Jean Carter, died from a fatal drug overdose ... TMZ has learned.
Bobbie's official cause of death is intoxication by the combined effects of fentanyl and methamphetamine ... according to the Hillsborough County Medical Examiner in Florida.
According to new legal docs, obtained by TMZ, the M.E. ruled Bobbie's death accidental.
As we first told you ... Bobbie Jean died two days before Christmas 2023, when she was found unresponsive in her bathroom while on probation on a drug-related charge.
The Medical Examiner's report says Bobbie Jean's roommate had contact with her at 6:30 AM on Dec. 23 ... but shortly after, around 7 AM, the roommate found Bobbie Jean unresponsive on the bathroom floor and called 911.
The docs say first responders tried life-saving measures on Bobbie Jean but they were unsuccessful and she was transported to a Tampa hospital, where, at 8:02 AM, she was pronounced dead.
Bobbie's since been buried in Florida. She was 41.