The US Supreme Court on Monday refused to hear the appeal of a former graduate student who was sued by the recording industry for illegally downloading music, letting stand a $675,000 judgment against him for violation of copyright laws. It was the first time the high court was asked to weigh in on the issue of using the Internet in violation of copyright laws and the application of those laws in deciding civil penalties, and the case was one of the first to hold a person responsible in the courts for illegally downloading music.