I concur with you that the investigators or the 12 LE agencies involved in the investigation are not involved in any type of cover-up. However, mistakes were obviously made early in the investigation.
As far as me changing my mind, I will just say I have a lot of mixed feelings about the identity of the killer or killers. I originally thought it might have been a police impersonator or a rogue police officer acting on his own. Then, I shifted to the girls being killed by someone they (well JB) knew. But, as the investigation has lingered for 19+ years, I've started to realize that if these murders were something simple and the motive was obvious, the case would have solved the case by now. Then, this past winter, I received a tip from someone who gave me some info I feel is very solid. The person they were suspicious of was a stranger to the girls. The info was passed on to LE. Time will tell if the info is good or not.