Last week, Fusion GPS founder Glen Simpson gave his written testimony to the Senate Judiciary Committee regarding the phony dossier about Donald Trump the company produced. The question that Sen. Chuck Grassley (R-IA) has asked repeatedly and has yet to receive an answer to is simple: Who originally paid Fusion GPS to investigate Trump? When the story came out last year, it was reported that a “wealthy Republican donor” was Fusion GPS’s original client. It was not until later that Hillary Clinton’s campaign then hired the firm. Simpson, however, is still refusing to identify this client.

So, who is this mysterious individual? It’s looking less likely than ever that one of Trump’s Republican primary opponents is responsible. In fact, the “wealthy Republican donor” description doesn’t necessitate that the individual in question was actually a card-carrying member of the GOP, as it is a well-established practice that those with various business interests often donate to both parties to build political favorability. Trump has admitted to doing so himself.

A second curious angle to the dossier mystery regards the FBI’s involvement and use of the discredited document. The Senate Judiciary Committee has sent repeated requests that the FBI make two of its top agents available for questioning on matters regarding the dossier. The FBI has so far refused. The question Grassley wants answered is whether the FBI used the dubious dossier as a pretext to gain FISA approval for surveillance of Trump campaign personnel.

There are many questions remaining that need answering before the truth behind the whole Russian election interference is fully understood and known. But what is pretty clear is that there is still no evidence of collusion.