Drew Barrymore’s half-sister, Jessica, was found dead in her car last month of a suspected suicide, and now a coroner has released an official cause of death.

Barrymore, 47, had a mixture of methamphetamine, alcohol, methadone, tramadol and nordiazepam in her system when she died, but the San Diego County Medical Examiner’s Office says it was likely an accidental overdose. She was Drew Barrymore’s half sister through their father, John, and had different mothers. Drew released a statement after Jessica’s death, saying the two of them had only met once.

“Although I only met her briefly, I wish her and her loved ones as much peace as possible and I’m so incredibly sorry for their loss,” the actress said.

John Barrymore had four children, but Drew reportedly has had a rocky past with her family and it’s not clear how close she was with her siblings. He died in 2004 after a battle with cancer, but the actress made sure he was taken care of while he was sick even though they were estranged for years before that. She said in January of this year that her famously difficult relationship with her mother, Jaid, had come to an impasse.

“I’ve always been empathetic toward my mom, and I was even more so when I had a kid and we had a really amazing conversation about it. However, [becoming a mom] hasn’t enabled me to lessen the distance. It’s the hardest subject in my life. I’ve never just been angry with her. I’ve always felt guilt and empathy and utter sensitivity. But we can’t really be in each other’s lives at this point,” she said in a Marie Claire interview.