A man who misled federal authorities into thinking that a Muslim student he met on a social networking Web site planned a terrorist attack on the Sears Tower in Chicago has pleaded guilty to the hoax.

Adam Hart, 22, pleaded guilty in U.S. District Court in Boston on Wednesday to one count of maliciously conveying false information. He is scheduled to be sentenced on Oct. 16, and could be ordered to serve up to 10 years in prison.

Hart was a student at the University of Massachusetts-Dartmouth in April 2006 when he sent an e-mail to the National Security Agency claiming that a University of Chicago student he met on Facebook Inc.'s popular online site was planning to detonate a bomb at the landmark skyscraper.

The hoax prompted increased security at the building and an investigation of the person Hart identified.

The investigation revealed that Hart sent e-mails containing racial slurs to the man in the days before he contacted the NSA.

A call to Hart's lawyer was not immediately returned on Thursday.