ANCHORAGE, Alaska (AP) — A Bangladeshi man accused of using social media to trick teenage girls into sending him sexually explicit images — and then threatening to share them with their friends and family if they didn't send more — has been transported to Alaska to face federal charges of child sexual exploitation.

Zobaidul Amin, 28, pleaded not guilty during an initial court appearance in Anchorage on Thursday after the FBI took custody of him in Kuala Lumpur, Malaysia, where he had been studying medicine and facing related charges, U.S. prosecutors wrote in a detention memorandum.

“Amin delighted in sexually abusing hundreds of minor victims over social media,” the document said. “He bragged about causing victims to become suicidal and engage in self-harm. He shared hundreds of nude images and videos of minor victims all over the internet and encouraged other perpetrators to do the same.”

A federal grand jury indicted Amin in 2022 on charges including child pornography, cyberstalking and wire fraud. He adopted false identities, often posing as a teenager, to trick victims into sending him explicit images, prosecutors said.

The investigation began when a 14-year-old Alaska girl reported her abuse to law enforcement, saying that after she had stopped communicating with him, he followed through on his threats by sending pornographic images of her to her friends and followers.

In executing dozens of search warrants and subpoenas, investigators eventually learned his identity and realized he had done similar things to hundreds of minor victims, prosecutors wrote. The only way to get him to stop demanding more images, Amin told the girls, was to recruit other victims, the document said.

“Because he was in Malaysia and his victims were primarily in the U.S., Amin viewed himself as untouchable by law enforcement,” prosecutors wrote. “In one conversation, he told a minor victim that the ‘cops won’t do anything,’ and the ‘cops won’t track me down because I live no where near u.’”

Efforts to extradite Amin to face charges failed, but with the assistance of the FBI, Malaysian authorities brought charges, the Justice Department said. He was released on bail during the proceedings, and eventually the U.S. succeeded in having him expelled from Malaysia. The FBI took him into custody and flew him to Alaska.

“The FBI’s commitment to protecting our children from exploitation doesn’t change whether an offender is here in the United States or overseas,” FBI Director Kash Patel said in a news release.

U.S. Magistrate Judge Kyle Reardon on Thursday ordered that Amin remain in custody while his case proceeds.