It's based on the idea that if I own one Prem club and I want to own another one, but the rules don't let me. So I gift you money but on the condition you buy this second club with it, and I will let you be boss of this second club except i'll still make the big decisions (like how much stake and when to sell).
This is the working theory the journos are going on based on the documents they have. It's almost impossible to prove this unless they have more private correspondence documentation, and even if they did prove it, it would still be up to the Prem/FA as to how it'll be investigated and if there'll be any consequences.
Realistically, nothing will be proved decisively, but as a result of this investigation the Prem/FA will publicly tighten up ownership checks and introduce a couple of stricter rules. For us, our involvement in the investigation may still have negative consequences, such as less willingness for external investment in the new stadium. This is pure conjecture, tho'.