Dre made the demand to the San Mateo, Calif.-based Napster Inc. in a letter, hot on the heels of an April 14th lawsuit filed by Metallica against Napster and three universities alleging they encouraged users to trade songs and recordings without permission.

Lawyer Howard King, who also represents Metallica in its complaint, sent the letter to Napster acting CEO Eileen Richardson on behalf of Dre.

“We wrote a letter… basically putting them on notice that the listing of his songs and masters on Napster and the facilitation of the transfer of those files constitutes an infringement of his copyright,” King told Reuters.

“Dr. Dre has not committed to suing them, but that would be the logical conclusion if they don’t take it off their site,” he said.

“It has never been Napster’s intention to belittle the importance of an artistic production, and we are very passionate about helping bands understand the value of what we offer. Nevertheless, technological advances over the last several years are restructuring the entertainment business,” Richardson said in a statement responding to the Metallica suit.

In a somewhat ironic twist, Lucasfilm, Ltd., the movie production company of George Lucas, filed suit alleging copyright infringement — among other things — against Dr. Dre last week over his use of the “THX Deep Note” sound to open his latest album, Chronic 2001.