Updated

An Indiana man has agreed to plead guilty to charges alleging that he tricked about a dozen teenagers from several states into stripping or performing sexual acts for him via webcam and then used recordings of those sessions to coerce them into making even more explicit videos.

Richard Finkbiner, who lives in the western Indiana community of Brazil, signed an agreement filed in federal court in Terre Haute on Wednesday in which he will plead guilty to child exploitation, extortion and possession of child pornography in exchange for a recommended sentence of 30 to 50 years in prison.

U.S. Attorney Joe Hogsett previously said prosecutors intended to seek an effective life sentence if a jury convicted Finkbiner.

Prosecutors say Finkbiner met his victims, who were mostly male, in online chat rooms. The teens thought they were looking at live images of people — including a couple, in at least one instance — who were acting sexually and encouraging the teens to do the same, but the images were actually recordings Finkbiner was showing them. He would later contact the teens again and threaten to upload the images to porn websites unless they made more videos for his private use, prosecutors say.

The alleged victims were all between the ages of 12 and 16. Prosecutors say Finkbiner victimized children in Indiana, West Virginia, Iowa, Wisconsin, Ohio, New York, Michigan, Illinois and Colorado.

Prosecutors say the case is an example of "sextortion," a crime authorities are seeing with greater frequency in which Internet predators catch victims in embarrassing situations online and threaten to expose them unless they create sexually explicit photos or videos.