Celtic's signing of Lassad Nouioui has been called into question after Levante claimed the striker broke an agreement with them to join the Bhoys.
The Turkish forward signed a two-year contract at Parkhead, but now faces the prospect of his switch to Scotland being dragged through the courts.
Levante claim Nouioui had already signed for them and Alberto Gill, a director at the Primera Liga outfit, insists they will seek legal advice.
"Our club reserves the right to use legal matters to investigate this transfer," he said. "And it is possible it could be reported to FIFA.
"We were told by his representatives that he would be in for training, only to later discover he was already on a plane to Scotland."
Nouioui, though, is turning a blind eye to the controversy he has caused and has expressed his delight at securing a move to Celtic.
The 26-year-old told the club's website: "I'm absolutely delighted. Celtic is a huge club with a fantastic support. I know all about the wonderful atmosphere at Celtic Park and can't wait to play there."