Merseyside Police are considering a letter from the mayor of Liverpool, Joe Anderson, in which he calls for an investigation into the circumstances surrounding Ross Barkley’s £15 million move from Everton to Chelsea.

Barkley was confirmed as Chelsea’s first signing of the January window last week, less than six months after a proposed £30m deal dramatically fell through in the final hours before the summer transfer window deadline in August.

Sources told ESPN FC at the time that Barkley, whose Everton contract was due to expire this summer, had decided to postpone a decision on his future to give himself time to fully recover from a serious hamstring injury suffered in training.

Barkley did not make a single Everton appearance in the four months leading up to the January window and, with six months left on his deal at Goodison Park, the possibility for interested clubs to acquire him for nothing at the end of the season significantly impacted his market value.

In the letter, which was also sent to the Football Association and Premier League, Anderson claimed that Barkley’s move to Stamford Bridge might have been deliberately delayed in order to financially benefit the player and Chelsea at the expense of Everton, who have no plans to submit a formal complaint.

“At best, this represents a very poor deal for Everton Football Club,” Anderson wrote. “At worst, it could be seen as a deliberate attempt to drive down a player’s value in the transfer market so as to benefit the player, his agent and the buying club.

“I am so concerned about the circumstances surrounding this transfer that I am asking the appropriate police authorities to consider whether any fraud has taken place.”

The Times reported on Wednesday that Chelsea paid Barkley’s agent £7m on top of the £15m received by Everton to secure the deal. The Premier League champions declined to comment on the size of the commission or Anderson’s accusations when contacted by ESPN FC.