A Minnesota teenager known online as "teekid" was arrested and placed on electronic monitoring Friday for allegedly unleashing a version of the "Blaster" computer worm that infected thousands of computers.

U.S. Magistrate Judge Susan Richard Nelson told Jeffrey Lee Parson not to access the Internet or any other network connection as a condition of his release. He did not enter a plea during his initial court appearance.

Parson, a physically imposing 18-year-old, admitted during an interview with the FBI and Secret Service agents that he had modified the original "Blaster" infection and created a version known by a variety of different names, including "Blaster.B.," court papers said. At least 7,000 computers were affected by Parson's worm, Assistant U.S. Attorney Paul Luehr said Friday...