Arsenal have confirmed they are investigating “as a matter of urgency” whether academy coach Mark Arber bet on the signing of Mesut Ozil.
Former Dagenham and Dartford defender Arber, whose father Bobby has also worked for the Gunners as a scout, posted a Tweet on his personal account, 1Arbs, on Monday that suggested he had bet on Germany midfielder Ozil's impending move to the Emirates Stadium.
"Lovely bit of 14-1 Mesut," he wrote.
The Barclays Premier League club are now looking into the potential breach of gambling rules.
A club spokesman said: "We take this very seriously.
"All Arsenal employees and workers are well aware of their responsibilities in this respect and we are looking into this as a matter of urgency."
If Arber had bet of the arrival of the 24-year-old, who completed a club-record £43million move from Real Madrid late on transfer deadline day, the 35-year-old is likely to have broken terms highlighted in the Football Association's guide to betting rules.
The rules state: "You are not allowed to place a bet on a game or competition in which you have any influence, either direct or indirect.
"The above includes all bets related to the following: Any other events involving your club or other clubs playing in the same league competition (such as next manager markets)."