The Naval Academy has seized the desktop computers of almost 100 midshipmen as part of an internal probe into whether students at the military college are using the Internet to illegally download copyrighted movies, music and software, a source said yesterday.

Academy officials confiscated the computers while midshipmen were in class Thursday, a month after entertainment industry groups sent a letter to colleges and universities nationwide, including the academy, requesting a crackdown on Internet piracy.

Academy spokesman Cmdr. Bill Spann confirmed the existence of an investigation but would not provide details. Students found to have improperly downloaded copyrighted material could face penalties ranging from court martial and expulsion to a loss of liberty, he said.

The academy gives every midshipman a computer within the first few weeks of school. About 4,000 students attend the officer-training college, which recently added information technology to its list of majors.

The Oct. 3 letter, from groups representing the motion picture and music industries, asks college presidents to monitor students' compliance with copyright laws and says that "peer-to-peer networks," such as the now-defunct Napster, are often a conduit for illegal trafficking in copyrighted software, video games and music.