MONTGOMERY, Ala. (AP) — An Alabama man has pleaded guilty to child porn and extortion charges after he was accused of posing as pop sensation Justin Bieber online and convincing young girls to send him inappropriate photos.

Christopher Patrick Gunn of Montgomery pleaded guilty Thursday. Court documents state that the 31-year-old Gunn promised girls between the ages of 9 to 16 tickets and backstage passes to a Bieber concert or otherwise extort them to provide sexually explicit photos and videos.

An indictment alleges that Gunn would also pose as a new kid in town on social media sites like Facebook.

Gunn has been charged with two counts of producing child pornography, 15 counts of interstate extortion and seven counts of internet stalking.

Based on his guilty plea, Gunn faces no less than 25 years.