Crystal Palace signing Cheick Doucoure's lawyer has alleged blackmail and attempted extortion from several parties related to his transfer.

Doucoure joined Palace from Lens for €22.5 million (£19m), plus €5m in bonuses.

In a statement, Doucoure's lawyer Alex Rutman said: "Since the announcement of his transfer from RC Lens to Crystal Palace, Mr. Cheick Oumar Doucoure and his entourage are victims of blackmail and an attempt at extortion from several individuals acting in concert (a players' agent and a photographer, supported by a journalist), clearly lured by the profits supposedly generated by this transaction.

"These individuals claim, with false evidence, that my client would have a double identity and demand the payment of a sum of money in return for their silence.

"Several Whatsapp messages to this effect, accompanied by false documents, have thus been addressed to my client and his entourage over the past few days.

"This situation is very serious and obviously unacceptable.

"My client and his entourage will not yield anything in the face of such actions which expose their perpetrators face severe criminal penalties

"All appropriate legal actions will therefore be taken, both criminally and civilly, against these three individuals but also against all those who would support, endorse or relay, in any form whatsoever, such actions and/or such slanderous accusations."