Four teenagers who sent racist and threatening tweets to former footballer Stan Collymore have been spoken to by police.
But Staffordshire Police said it had been unable to trace other abusive users after Twitter failed to pass on their details.
The ex-Liverpool player, who received the tweets between January and May, praised the police force for their response to the abuse.
"Cannock and Staffordshire Police have been exceptional. It's Twitter refusing to give info. Twitter, beyond UK law. For now," he tweeted on Monday.