I thought you were addressing LE lying to the public, but I wasn't "really" sure, so I tried to cover both points: LE lied to Michael and his parents, but they (as far as I know) used qualifiers when speaking to the public. (Along the lines of "It is my understanding that.....instead of saying "this is what happened." "I'm not at liberty to say" is used when they don't want to release information, and I believe that was used alot!) Since I have friends in LE, I do tend to parse their words with a great deal of attention: it is sometimes as interesting to note what is NOT said as what IS said. I learned this while sitting with my friends watching an LE/FBI news conference during the search for the identity of one of Louisiana's serial killers. My friend would say "Did you catch that? Think about that, because it is very important.") My friend is a lieutenant in LE, decades of experience, so he really got my attention!
In this case, I believe the fact that "appearance of blood" instead of "appearance of blood spatter" MAY be very significant. Or it may mean the spokesperson is just an old country boy using the least amount of words he possibly can! The sheriff alluded one day something along the lines of "everyone thinks we have no eye-witness, but "I" didn't say that!" which could lead one to believe there is an eye-witness and LE just hasn't released the info to the public, OR "there isn't an eyewitness, but I'm not telling you that!"
Although some locals have posted that this particular department of LE has had some rather serious credibility problems in the past, I'm willing to give LE the benefit of the doubt right now.......that they aren't deliberately, corruptly accusing Guy, that they may have more evidence that is being held back that explains their belief that Guy is the murderer, etc. HOWEVER, the possibility that they've developed tunnel vision and "bulldogged" the situation does exist.
I totally, totally agree with your last paragraph! I will always side on the possibility of INNOCENCE until I have all the facts to make a permanent decision!