A few years ago, the FBI came to my house asking about a friend of mine that they were looking for. I told them what I know about him and they left. I never heard from them again. I am applying for my citizenship now, can that incident delay the FBI name check and cause my application to take longer to process? What kind of problems might that incident cause me? The guy that they were looking for was never arrested by them or charged with any kind of crime.
I have never been arrested or charged with any kind of crimes.
I doubt anyone can legitimately answer your question. That said, my guess would be no.
The answer provided is general in nature and should not be construed as legal advice as not all facts are know by the attorney, nor does the answering of this question create an attorney client relationship.
There may be some delays if your name is associated with some type of an FBI investigation, even if you were just questioned once. However, since you or your friend were never arrested or charged, it is more likely than not that your N400 application would not be denied solely on that basis.