Birmingham City owner Carsen Yeung is unhappy with the deals done for Ecuador pair Christian Benitez and Giovanny Espinoza.
The Mirror says Yeung is fuming after being hit with bills of around £6million for agents' fees and transfer instalments from before his recent £80m takeover.
And he has ordered a post-acquisition due diligence of City's books from July 2007 when he bought his original 29.9 per cent stake.
Brum's new vice-president, Peter Pannu, a former Hong Kong cop and barrister, is going through the club's books with their legal team.
And they are scrutinising closely the summer arrivals of Benitez and Espinoza.