NEW YORK CITY, NEW YORK: A 20-year-old female drug dealer has been detained on federal narcotics charges related to an inquiry into the OD death of Leandro De Niro Rodriguez, Robert De Niro's grandson. Sophia Haley Marks is charged with selling drugs to Leandro just before he was discovered dead in his New York City residence. According to the New York Post, Marks referred to as the "Percocet Princess," was taken into custody Thursday evening at 6 pm during an NYPD undercover sting operation.

Before purportedly selling De Niro's grandson the pills that resulted in his alleged overdose, the so-called "Percocet Princess" warned him that they might cause his death, as per Daily Mail. Leandro died at the age of 19 earlier this month. Although an official cause of death has not yet been established, authorities are looking into the possibility of a drug overdose. The question now is: Who is Sofia Haley Marks, and why did the police detain her in connection with Leandro's death?

Who is Sophia Haley Marks?

Sophia Haley Marks, dubbed the "Percocet Princess," is an alleged drug dealer who has been detained in relation to the horrific overdose death of Leandro. According to law enforcement officials, Marks, 20, is said to have sold Leandro drugs before he was discovered dead in his New York City apartment on July 2. According to the lawsuit, Marks allegedly sold fentanyl-laced counterfeit oxycodone tablets on three different occasions to Leandro.

She said nothing more than "good afternoon" to the judge as she appeared frail, pale, and stone-faced in a black T-shirt. Marks was remanded in custody after her Friday court appearance in Manhattan on three counts of drug distribution. Marks then responded "yes" to a series of inquiries, including whether she was aware of the accusations. Marks is charged with two counts of supplying and possessing with a purpose to distribute fentanyl along with one count each of alprazolam and fentanyl. She might spend as much as 60 years behind bars if found guilty of all charges. The next court date for her is August 14.

'I don't wanna kill you'

According to the criminal complaint, Marks allegedly sold Leandro fake Oxycodone and Xanax with fentanyl in them the night before he was discovered dead. Marks was arrested without bail on federal drug charges in Manhattan on Friday, July 14. Legal records claim that police found drugs at the site of Leandro's death and that they utilized the teen's phone to discover text chats with Marks in which Leandro requested to purchase oxycodone and Xanax in the days preceding his death.

According to the sources, when Leonardo initially texted Marks on June 30 to get "thirties" -- blue counterfeit Oxycodone embossed with the number -- she allegedly responded that they might be dangerous. Marks bluntly asks Leonardo through text: "Do you really need them? I don't wanna kill you. I just don't like serving u them cuz they not script." She allegedly agreed to sell him three "pressed" Oxycodone pills and two Xanax pills for $105 after Leonardo apparently questioned whether the pills were cut with "fent or h," which is a reference to fentanyl or heroin.

According to law enforcement sources, Marks allegedly sent the tablets to Leandro via car service at around 9:30 pm on July 1. Leandro was then cautioned by the 20-year-old dealer to "don't go overboard with these." Less than five hours later, Marks checked on him if he was doing ok, but never got a reply.

The lawsuit states that Marks subsequently sold 50 oxycodone tablets laced with fentanyl to an undercover police officer for $1,000. She allegedly admitted to the officer that during one of the transactions, weeks before Rodriguez's alleged overdose, a friend of hers, age 19, died after taking one of the pills on June 14. Officers claimed to have discovered 156 pills and $1,500 in cash when they took her into custody on Thursday night.

'Someone sold him fentanyl-laced pills'

According to authorities, Leandro was found dead in his $950,000, one-bedroom apartment on July 2 from what appears to be an overdose. On July 5, Leandro's mother, Drena De Niro allegedly lambasted Marks on Instagram for selling drugs that were fatal. She replied to a user who had inquired as to his whereabouts, "Someone sold him fentanyl-laced pills that they knew were laced yet still sold them to him, so for all these people still f---ing around selling and buying this s---, my son is gone forever."

In a statement last week, Robert De Niro expressed his "deep distress" at the loss of his "loved grandson Leo."