The cause of death for Leandro De Niro Rodriguez, the grandson of Oscar-winning actor Robert De Niro, has been determined.

According to an email sent to CNN from the New York City Medical Examiner's Office, the 19-year-old's death in July was the result of a toxic combination of fentanyl, bromazolam, alprazolam, 7-aminoclonazepam, ketamine, and cocaine.

His death has been ruled an accident.

A woman was arrested in connection with the teen's death.

Sofia Marks was taken into custody on a charge of selling drugs to a minor, a law enforcement source told CNN later in July. Marks has not been charged with murder, the source said at the time.

Actress Drena De Niro, Robert De Niro's daughter, wrote about the loss of her son in a post on Instagram when it happened.

"You have been my joy my heart and all that was ever pure and real in my life," the caption read in part. "I don't know how to live without you but I'll try to go on and spread the love and light that you so made me feel in getting to be your mama. You were so deeply loved and appreciated and I wish that love alone could have saved you."

She tagged her son's father, artist Carlos Rodriguez, who goes by Carlos Mare, in the post.