Drena De Niro has shared the cause of death for her 19-year-old son.

Leandro De Niro Rodriguez, the grandson of Oscar-winning actor Robert De Niro, recently died after ingesting fentanyl, his mother wrote on social media.

"It is with immeasurable shock and sadness that we say goodbye to our beloved son Leo," Drena De Niro posted Monday in a statement on her verified social media. "We thank you for the outpouring of love and support and ask that we are given privacy at this time to process this inconsolable grief."

In comments on that post, a follower asked how the teen actor died -- and why.

"Someone sold him fentanyl laced pills that they knew were laced yet still sold them to him so for all these people still f**king around selling and buying this sh*t, my son is gone forever," De Niro wrote in response.

Nearly 70,000 people in the US died of drug overdoses that involved fentanyl in 2021, almost a fourfold increase over five years, according to a recent report from the US Centers for Disease Control and Prevention. By 2021, about two-thirds of all overdose deaths involved the potent synthetic opioid, it found.

Drena De Niro had announced her son's death in an Instagram post on Sunday.

"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."

An actress, De Niro is the daughter of the legendary actor, who also expressed his grief over the loss.

"I'm deeply distressed by the passing of my beloved grandson Leo," Robert De Niro said in a statement to CNN. "We're greatly appreciative of the condolences from everyone. We ask that we please be given privacy to grieve our loss of Leo."

Leandro De Niro Rodriguez had appeared, along with his mother, in the 2018 film "A Star Is Born," starring Bradley Cooper and Lady Gaga. His other acting credits include "Cabaret Maxime" in 2018 and "The Collection" in 2005, according to IMdB.