Leeds United chairman Massimo Cellino is being investigated by the Football Association, just one day after returning to the club's board.
The FA is looking at whether the Italian sanctioned an unauthorised payment to an unlicensed agent in Ross McCormack's transfer to Fulham last year, reports BBC Radio Leeds.
McCormack, 28, joined the Craven Cottage side for £11m in July.
Cellino is also being accused of breaking third-party ownership rules.
Brazilian forward Adryan, 20, spent the season on loan at Elland Road from Flamengo.
The Daily Mirror reports that they have seen documents that the deal to bring the player to the club would have seen Leeds pay Rio de Janeiro firm RP4 Football Management 20% of any sell-on fee if they had signed Adryan permanently.
The Brazil Under-20 international has now returned to his parent club after making 13 appearances for the Whites.
The FA's third-party ownership regulations prevents clubs from making payments to third parties except for in exceptional circumstances.
Cellino returned to the club on Thursday after serving a Football League ban for being found guilty of tax evasion in Italy.
Meanwhile, BBC Radio Leeds reports that midfielder Lewis Cook, 18, is close to signing a new deal.
Cellino contacted the station to say the contract, that will keep Cook at the club until 2017, is now with the player and his agent.