ST. JOHNS COUNTY, Fla. - The FBI is asking for the public's help finding hundreds of victims in what could be the nation's largest "sextortion" case.
It involves a St. Johns County man who's in prison for using social media to extort teenage girls to send sexually explicit photos.
Lucas Chansler, 31, pleaded guilty last year, and was sentenced to 105 years in federal prison.
FBI agents said Chansler took advantage of about 350 teenage girls from across the U.S., Canada and the United Kingdom, only about 100 of which had been identified.
Federal agents will be holding a news conference Tuesday to provide never-before-heard details in hopes of finding about the other 250 of the victims who have not yet been identified.
Investigators said Chansler went on a four-year "reign of terror" where he pretended to be a 15-year-old boy online. He met young girls, convinced them to send him inappropriate photos and then extorted them.
Agents said once he got those pictures, he threatened to post them for everyone to see, unless they sent more inappropriate pictures. Some of the girls were as young as 13.
Investigators arrested Chansler in 2010 and found 80,000 explicit pictures and videos on his computer. Some of the teens have been identified, but most have not.
FBI agents said the illicit, underage photos are still being traded among pedophiles on the Internet. They also said that the screen names that Chansler used are being released in Tuesday's news conference.
Anyone with information about Chansler is urged to come forward to help with the ongoing investigation.
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