Cardiff City have reportedly begun to investigate whether Emiliano Sala was registered to play in the Premier League before he was killed in a plane crash in January.

Sala and pilot David Ibbotson were involved in a crash over the English Channel on January 21 after the Argentine had flown back to France to say goodbye to his former Nantes teammates.

Cardiff agreed to pay £15m to complete the signing of the forward, but according to The Telegraph, it is currently unclear whether Sala had finalised his transfer to the Welsh club.

The report claims that Sala's contract was returned to Cardiff with it being deemed that it was 'non-compliant with Premier League rules', and it required Sala to sign an amended deal.

Nantes had been demanding the first instalment of what they are due to receive from Cardiff, although that is likely to be delayed due to the dispute between the two clubs.