George Nader, a top United Arab Emirates adviser who was a witness in special counsel Robert Mueller's investigation, remains in custody Thursday night after the judge decided to schedule a detention hearing to take place Friday.

Nader was charged with one count of child pornography. If convicted, Nader faces a maximum sentence of 40 years in prison.

Nader was present in the Alexandria, Virginia federal court Thursday. He spoke softly when answering Judge Ivan Davis' questions. Nader wore an olive prison uniform with a navy undershirt.

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He is accused of transporting child pornography. The charging document says that in January 2018, after a flight from Dubai, Nader was stopped at Washington-Dulles Airport for questioning by the FBI on an unrelated matter. While searching the three phones Nader had declared, the FBI agent uncovered several files containing child pornography.

Nader, a Lebanese-American businessman was interviewed by the special counsel about whether he had funneled money from the United Arab Emirates to Donald Trump's election efforts. According to the New York Times, Nader was also present at a 2017 meeting in the Seychellse involving Blackwater founder and informal Trump adviser Erik Prince and a Russian associate of Vladimir Putin.

This is the third time Nader has faced child pornography charges. In 1991 he pleaded guilty to the same charge, after two reels of videotape hidden in candy tins were seized from him at Dulles Airport, according to the charging document.

In the 1980s, Nader was indicted for receiving child pornography in the mail, but a judge found that the material was obtained through a warrant that was too broad and therefore violated Fourth Amendment protections against unreasonable search and seizure.

A preliminary hearing was also scheduled for Monday at 3 p.m. before federal Judge Buchanan.

Alexandra Chaidez and Donovan Dooley contributed to this report