Whisperer, I feel your frustration as well with the lack of information. But it's not LE's job to to answer every question the public has about an investigation. It would not only be harmful to the investigation, but would be a never ending job. It is their job, as I see it, to release that information that would be beneficial to the investigation or protect the public at large if there was an ongoing threat. Having said that, on certain points, I do believe it would have been beneficial to inform the public, such as what possessions of Holly's were missing.
TC was a suspect...for obstruction of justice...and they treated him as such. There is also a difference between sleuthing and inserting yourself into an investigation or case. Personally, I think TC went overboard and it drew a reaction from LE that may have been overboard. As far as what they are afraid of, they are afraid of an outsider destroying a case or investigation.