How about you quote the whole thing:"interviewed four unnamed FBI officials familiar with the agency's probe into the insurrection "
Then how about you go read the actual Reuters article take note of the very first paragraph (quoted below) and the bold type:
IT does not indicate that those Law enforcement officials are from the FBI. If that where true, they wouldn't be playing a word game and would call them FBI officials. This is what happens when media outlets start using only one media source (The only media source) and fail to comprehend what is being said, and or put their own unsubstantiated spin on things to manipulate the weak minded (you) into believing something that has no legitimacy behind it .. There is no indication that these 4 unnamed law enforcement officials are from the FBI.