The FBI has been under fire in the past year for various and sundry crimes against logic and probity and this is much more deeply ingrained in the culture of the political agency since its founding. It was developed as the original secret police organization for the US government to wield to seek its political ends.
The sacking of Comey the Commie is simply the latest above-ground evidence that the agency is broken for its ostensible purpose of crime investigation and simply exists as an American analog to the Cheka, NKVD, KGB and Gestapo. It even reflagged its purpose with the blank check moniker of national security.
It has relied on Lysenko-style science that would make the Russians blush in embarrassment. Fingerprint and hair analysis are simply the most recent blunders of applying junk science to crime fighting.