I said this already...but I doubt the series of events is as confusing to LE as it is being reported to the public. I think they pretty much know what she did or did not do, if she went home, if she was alone in the car, etc. and whether or not BF/friend is telling the truth. But what they (LE) are not doing is correcting any bad information being reported or making any attempt to clarify the timeline or sequence of events. This could mean they know plenty and are just hoping to find Adrienne in order to proceed with charges. The way they have been searching the area, it does not appear that they think she took off, or was taken away in another vehicle.
But...it could also mean they have no idea what happened to her and are just searching around the area for lack of other leads. In the case of Jessica H. in Michigan, there has been much outcry due to a lack of local searching, as LE believes she was removed in a vehicle, so she could be anywhere. It is impossible to deduce from LE's actions what they know or don't know. What I have learned from following hundreds of MP cases is that for the most part,LE is not really prepared to handle them. IMO, they tend to keep everything secret, worrying too far in advance about trials and evidence, instead of letting the public help them.
The only thing that matters is finding the person...the rest can come later. JMO