Officials are addressing what led to the untimely death of Robert De Niro's grandson Leandro De Niro Rodriguez.

The 19-year-old died from an accidental drug overdose, the New York City's chief medical examiner confirmed to TMZ Aug 8. More specifically, his cause of death is attributed to the "toxic effects of fentanyl, bromazolam, alprazolam, 7-aminoclonazepam, ketamine, and cocaine."

A spokesperson for the NYPD previously confirmed to E! News that Leandro was found unconscious and unresponsive inside a New York City residence on July 2. He was pronounced dead at the scene.  

Shortly after Leandro's passing, his mother Drena De Niro, the daughter of Robert and his ex Diahnne Abbott, spoke about the circumstances of his death, alleging he was sold fentanyl-laced pills.

"So for all these people still f--king around selling and buying this s--t," she wrote in the comments section of a July 3 Instagram post, "my son is gone forever."

Drena, who shared Leandro with artist Carlos Mare, also paid tribute to her son after his tragic death, describing him as a "beautiful sweet angel."

"You have been my joy my heart and all that was ever pure and real in my life," she wrote in a July 2 Instagram post. "I wish I was with you right now. I wish I was with you. 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."

The 51-year-old noted that Leandro was "so deeply loved and appreciated."

"I wish that love alone could have saved you," she continued. "I'm so sorry my baby." 

Drena's father Robert also spoke out about the loss of his grandson, sharing that he was "deeply distressed by the passing," adding that the family was "greatly appreciative of the condolences from everyone."

A suspect was arrested on federal drug distribution charges and taken into custody on July 14 in connection to the case.

For the latest breaking news updates, click here to download the E! News App