(CNN) A high-ranking Democratic senator suspects James Comey's termination as FBI director is the direct result of the ongoing investigation into Russia's alleged interference with the US election.

"If you're in the Trump White House, and you know that they are looking for collusion by members of the Trump campaign, it's pretty clear they are in hot pursuit when they are asking for more resources," said Dick Durbin, a Democrat from Illinois. "At that point, they decided the best thing to do is terminate James Comey."

Durbin, the Senate minority whip, shared his theory Wednesday with Wolf Blitzer as the host of "The Situation Room" asked about rumors centering around an ask for additional funds.

"CNN ... is reporting that earlier in the week Comey requested more resources from the Deputy Attorney General Rod Rosenstein, for the entire Russia investigation," stated Blitzer, before posing a direct inquiry to his guest: "What do you know about this request?"

"I've heard the same information that you've reported," replied Durbin. "I've heard it from credible sources, and I believe it happened," Durbin replied.

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