When the charges against TS first came down, quite a few folks assumed the 1st degree murder charge was there because she planned to kill Gannon.
As it turns out, that wasn't the reason for that charge at all, it's because under the law in Colorado, if you're a person in a position of trust to a child under the age of 12, and you cause their death (in a number of ways as defined by the law) you're automatically going to be charged with 1st degree murder. As well you should.
Likewise, the tampering with a human body charge lists a number of different ways one
might hide/damage a deceased person, with the intent of keeping justice at bay, but it doesn't mean all the things listed (or one or another) actually happened to that body. It just lists possible ways it
could have taken place.
All of this is 100% paraphrased, from the links to the exact revised codes that have already been posted, but are easily missed, since this thread moves like lightning.
I hope that helps.