the FBI, as part of our counterintelligence mission, is investigating the Russian government's efforts to interfere in the 2016 presidential election and that includes investigating the nature of any links between individuals associated with the Trump campaign and the Russian government and whether there was any coordination between the campaign and Russia's efforts.
Sounds ominous. Let's put some names on it.
That's it. All of the intrigue swirling around is enabled by keeping "the investigation vague" on a pretext that disclosing the names of the suspects would taint them, be harmful to their privacy, etc.
The details of contact between "a Russian" and one of the named targets of investigation are reasonably well described in numerous news reports. Not only does the public have a handle on the names, it also has a handle on the contacts.
Sessions was working as a senator, and told BY THE FBI to not bother disclosing those contacts on his disclosure forms.
Carter Page wants to testify. He was unmasked and under FISA warrants. Congress won't let him testify, he opens up the can of worms about the politicization of the FBI under Obama.
Flynn contacts have been cleared as "not criminal" by the FBI. The only FBI criminal investigation open on Flynn, inferred from Comey's testimony, are misleading investigators and maybe perjury. There is no "Russia" there.
Manafort is a little more complicated, but he was cut loose before the primary race was concluded, and I have never heard any allegation of a Manafort campaign action having any connection to Russia.
Comey has been keeping this Russia thing spinning by deliberately dragging his feet on the investigations, leaking to the press, and setting land mines.