Fired FBI Director James Comey's testimony before the Senate Select Committee on Intelligence has already resulted in several major revelations—including that he kept notes on his meetings with Trump because he "was honestly concerned he might lie about the nature of our meeting."

But another potential bombshell came out in Comey's testimony, while he was questioned by Sen. Ron Wyden (D-Ore.): unknown relations between Attorney General Jeff Sessions and Russia.

Comey testified that he believed Sessions would recuse himself from the Russia-related investigation for "a variety of reasons" and that there were facts Comey couldn't discuss in an open setting (i.e., not a classified session) "that would make his continued engagement in a Russia-related investigation problematic." 

Sessions did wind up recusing himself from the Russia investigation after the Washington Post revealed two contacts between Sessions and Russian ambassador Sergei Kislyak, contacts that Sessions hadn't mentioned during his confirmation hearing. 

During his testimony, Comey essentially testified that he believed there were "a variety of reasons" that would force him to remove himself from any investigation related to Russia, beyond what was reported by the Post. Because of classification, the nature of these entanglements hasn't been made public. This is significant because Sessions still holds his post as Attorney General, and had played a role in the recommendation of Comey's firing.

Sen. Kamala Harris (D-Calif.) later followed up with Comey on Sessions-related matters.