Evidence in the weeds

The trouble right now is that the FBI and Intel Agency must confront their duty in a conflicted environment. Their organization's missions are legislated. Their duty is to pursue them independently and professionally without political intervention.

President-elect Trump's lies are well documented. However, they are not purposely collected and analyzed. The process is random, at best.

"President-elect Donald Trump told a radio interviewer in October 2015 that he had met Vladimir Putin “one time … a long time ago” and that he “got along with him great” — a statement that conflicts with his later denials during the campaign that he had ever met or spoken with the Russian president. 

The newly surfaced audiotape, uncovered by a political opposition-research group, could fuel new questions about the precise nature of Trump’s past relations with the Russian president — a subject about which he has made multiple contradictory comments. It was released just hours after Putin, speaking from Moscow, denounced officials in the Obama administration as “worse than prostitutes” for circulating “nonsense” personal allegations about Trump that were allegedly collected by Russian intelligence." 

https://www.yahoo.com/news/tape-shows-trump-contradicting-himself-again-on-putin-meeting-213245455.html

The mission of the FBI is to protect the American people and uphold the United States Constitution. If a US presidential candidate's relationships are suspected to be conflicted in any manner, the FBI must investigate.

The intelligence agency is different.

"The employees of the CIA provide intelligence (or information) to the President, the National Security Council, and all other government officials who make and carry out US national security policy. 

We do not make policy or even make policy recommendations. That’s the job of the US executive branch, such as the State Department or the Defense Department. We provide these leaders with the best information possible to help them make policy involving other countries."

CIA 

The onus is on the FBI to vet and to investigate Donald Trump.

House Minority Leader Nancy Pelosi (D-Calif.) and other Democrats are insisting that the FBI investigate alleged links between the Trump campaign and the Kremlin to find out whether Russia has leverage over the incoming president. (Alex Wong/Getty Images)