The Recording Industry Association of America (RIAA) has sent "cease and desist" letters to four people it alleges were illegally offering hundreds of copyrighted songs over the Internet.
The names were handed over by Verizon, which until now has refused to reveal the identity of its punters accused of pirating music, claming the matter could have a "chilling effect" on Internet users.
Earlier this month, though, the US Court of Appeals rejected Verizon's request to stay an earlier court ruling ordering the ISP to turn over the identities of some of its subscribers.
At the time, RIAA president Cary Sherman said: "The Court of Appeals decision confirms our long-held position that music pirates must be held accountable for their actions, and not be allowed to hide behind the company that provides their Internet service.
"Given that an epidemic of illegal downloading is threatening the livelihoods of artists, songwriters and tens of thousands of other recording industry workers who bring music to the public, we look forward to Verizon's speedy compliance with this ruling."
According to the BBC, Verizon has now complied with the ruling and handed over the names and contact details of those concerned.
The RIAA has written to those concerned telling them to pack it in. It's not known what other action, if any, the RIAA might take. ®