The Mother Jones report is based on the claim of an unnamed “former senior intelligence officer for a Western country who specialized in Russian counterintelligence.” This person told the liberal magazine “that in recent months he provided the [FBI] with memos, based on his recent interactions with Russian sources, contending the Russian government has for years tried to co-opt and assist Trump — and that the FBI requested more information from him.”

The former intelligence officer also told Mother Jones that according to his sources, “there was an established exchange of information between the Trump campaign and the Kremlin of mutual benefit.”

The notion of “an established exchange of information” is consistent with Slate's report that a computer scientist — given the pseudonym “Tea Leaves” in a story by Franklin Foer — discovered what appears to be regular communication between a Trump computer server and a bank in Moscow. “Tea Leaves” and his colleagues, who originally set out to monitor cyberattacks, concluded that “this wasn’t an attack but a sustained relationship between a server registered to the Trump Organization and two servers registered to an entity called Alfa Bank.”

Adding to suspicions of a link between Trump and Russia is NBC's report that “the FBI has been conducting a preliminary inquiry into Donald Trump's former campaign manager Paul Manafort's foreign business connections,” according to unnamed “law enforcement and intelligence sources.”