A federal judge sentenced an Illinois man to two and a half years in prison Monday for taping ESPN sports reporter Erin Andrews in the nude.

The taping took place through a hotel-room peephole, and the video was posted on the Internet.

Michael David Barrett, 49, pleaded guilty to a federal stalking charge in December after prosecutors accused him of altering hotel peepholes so he could shoot video of Andrews while she was nude. In court papers, prosecutors stated that Barrett -- an insurance company employee from Westmont, Illinois -- posted as many as 10 videos of Andrews to the Internet.

Also in court papers, prosecutors said Barrett had posted videos of another 16 as-yet-unidentified victims to the Internet.

Barrett is free on bail and has been ordered to report to prison May 3, said Tom Mrozek, a spokesman for the U.S. attorney's office in Los Angeles.

In a statement issued through his attorney when the plea agreement was announced, Barrett expressed "deep regret" to Andrews "for his conduct that caused her so much pain."

Authorities believe that most of the videos were made at a hotel in Nashville, Tennessee, in September 2008. The peephole into Andrews' room was altered with a hacksaw, and the images appeared to have been taken with a cell phone camera, according to the charges against Barrett.

Andrews travels across the country covering college football games for ESPN. According to charges prosecutors filed against Barrett in October, she said that she became aware of the videos in July and that their posting caused her distress, anxiety and trouble sleeping.