Roberto Firmino's transfer from Hoffenheim to Liverpool has been or is currently being investigated by FIFA, according to a new book released by Football Leaks, with their Dirty Business of Football claiming that of the £29M stated transfer fee paid by Liverpool for the attacker, only £5.8M ever went to Hoffenheim.
The alleged wrongdoer in this case—if it turns out that there was one, and if the case is even an open and ongoing one given FIFA have offered no public comment on the matter—would not be Liverpool, meaning there is little for the club or fans to worry about at this stage in the matter.
Instead, any issues under investigation would concern Dietmar Hopp and Transfair, a company that helped to manage the actual transfer of the player and to settle outstanding third-party ownership issues. Hopp and Transfair are not connected to Firmino or his agency, Rogon Sportmanagement GMBH.
At the time of the transfer, there was talk about Hoffenheim only being entitled to between £15-20M of the transfer fee—the fee that was initially reported as what it would take for Liverpool to sign the player—with the balance of the £29M expected to pay off any outstanding third-party ownership claims.
Instead, according to Football Leaks, only days after Transfair's involvement in the Firmino transfer and with Hoffenheim only being sent £5.8M, Hopp withdrew his interest in the company and that following that the German club did not receive any further funds to which it may have had a claim.
Or at least all of that was true, to the best of Football Leaks' knowledge, at some point in the past. Whether any investigation into the case is still ongoing, or what FIFA's findings were if the case has since been closed or dismissed, is currently unknown.