NEW YORK >> A 20-year-old woman has been arrested on federal narcotics charges and is accused of selling the drugs that led to the death of actor Robert De Niro’s 19-year-old grandson, a law enforcement official said Friday.

The woman, Sofia Haley Marks, appeared in Manhattan federal court on Friday and agreed to remain behind bars until she requests bail at a later date. Prosecutors said they would oppose a request for her release.

Marks was arrested Thursday evening on three counts of narcotics distribution stemming from the sale of drugs to Leandro De Niro Rodriguez, the law enforcement official said. The official was not authorized to discuss details of the investigation publicly and spoke to The Associated Press on condition of anonymity.

Rodriguez was found dead in his Manhattan apartment on July 2. His mother, Drena De Niro, announced the death on Instagram. Amy Gallicchio, an assistant federal defender who represented Marks on Friday, said Marks planned to hire a lawyer. Gallicchio declined comment outside court.

U.S. Attorney Damian Williams said in a statement that at least one of the fake oxycodone pills sold by Marks was “taken by a teenager who subsequently died of a suspected overdose.” Rodriguez was not identified by name in court documents.

Williams said the arrest “was critical because, as we allege, Marks knew the pills could kill, and she continued selling them anyway.”

The prosecutor said fentanyl was now the primary killer of Americans from ages 18 to 49. An estimated 109,680 people died from drug overdoses in 2022, including about 75,000 from fentanyl and other synthetic opioids.

“More than cancer, car accidents, or gun violence. It is a law enforcement crisis and a public health crisis. And we are doing everything we can to stop it,” he said.

Rodriguez’s cause of death remains under investigation, a spokesperson for the city medical examiner’s office said.

When Drena De Niro announced her son’s death, she responded to a question to her post by writing that her son died after “someone sold him fentanyl laced pills.”

Rodriguez was the oldest child of Drena De Niro and artist Carlos Mare.

Like his famous grandfather, Rodriguez was an actor who had appeared with his mother in projects including Bradley Cooper’s 2018 remake of “A Star is Born.”

Robert De Niro said after Rodriguez’s death that he was “deeply distressed by the passing of my beloved grandson Leo.” A representative for him didn’t immediately respond to a message seeking comment about the arrest.

Associated Press writer Larry Neumeister contributed to his report.