We already know the roots of that investigation and have for quite a long time. Trump campaign member George Papadopulous revealed to an Australian diplomat that he had inside information about Russia's attempts to intervene in our election. This has been public information for about a year and a half. The problem for conservatives with this is that the FBI would have been absolutely insane NOT to open an investigation into the Trump campaign after that.
There have been two separate investigations into the beginnings of the investigation and they have all turned up nothing.
https://www.nytimes.com/2017/12/30/...-investigation-began-george-papadopoulos.html
This is turning into another Benghazi where when conservatives investigate something and don't get the answer they want they don't accept reality, they decide that just means they need another investigation.