We know that the local police visited her house, and that the FBI knew about it.

I don't think I'm being unreasonable in trusting the author that the officers said they were with the Joint Terrorism Task Force, which is one of a few plausible ways the FBI would know about local PD activity.

Her credibility on the big fact is established. What are we missing, then? The details on what the questions were? Whether or not they were asked about their Google history? Where the intel came from?