Teenagers spoken to after Stan Collymore racist tweets
Four teenage boys have been spoken to by police for sending racist and threatening tweets to ex-footballer Stan Collymore.
Mr Collymore said he had been racially abused and sent death threats via Twitter between January and May.
Staffordshire Police said four juveniles were dealt with "through restorative justice which Mr Collymore was aware of and happy with".
It failed to find others because Twitter did not assist, the force said.
Ch Insp Steve Morrey said: "Despite repeated requests for information made to Twitter regarding a number of other users we wanted to speak to in connection with this matter, Twitter have not supplied it.... therefore all lines of inquiry have been exhausted."
In response, Mr Collymore, who now works as a pundit for radio station TalkSport, tweeted: "Cannock and Staffordshire Police have been exceptional.
"It's Twitter refusing to give info. Twitter, beyond UK law. For now."
But he later tweeted part of a conversation between himself and Twitter which said after initial communications, Staffordshire Police stopped responding to requests for information by the social media giant.
Staffordshire Police has yet to comment.
A spokeswoman for Twitter has said it could not comment on individual accounts "for privacy and security reasons".
"[We] have a clear process for working with the police and are in ongoing communication with relevant UK police forces to make sure they are aware of our policies," she said.
She said it was also taking action to eliminate online abuse.