Investigators from the FA have questioned more directors from Luton Town FC over the club's finances.
Officials from the FA's compliance team spent several hours at Kenilworth Road on Monday afternoon talking to directors and employees.
Former chairman Bill Tomlins has already admitted breaking the rules regarding payment to agents.
Investigators are now looking at the possibility that the club may be in breach of two serious rules.
The FA will not make any statement until the compliance team has finalised its report in relation to a total of eight transfers.
Mr Tomlins, whose ex-manager Mike Newell made claims about corruption in the game's transfer market, stood down in the wake of the FA inquiry.
