I've seen a lot of references to DM being the ring-leader, or the mastermind, but there really isn't any evidence, other than the fact that because he has money, people are more likely to follow him than lead him.
Based on the real evidence that has been published, i don't see anything conclusive.
DM has been placed at the sunday testdrive based on the tattoo, and his general description matches that of one of the suspects identified by TB's wife, but she didn't see the tattoo, and based on the generality of her description, she may not be able to conclusively identify him. if she can, we don't know that, because LE have not provided that information.
DM is only connected to everything that happened after the three men left TB's residence in that the events occurred on his property, his mother's property, and involved a trailer owned by him. i haven't seen anything conclusively placing him at any of these locations in the last week. nothing shows him towing that truck, or visiting his mom's house, or being at his farmhouse. someone did those things, but maybe it wasn't him.
I'm not saying i don't think he's involved, and the charges indicate that LE have evidence saying he is somehow involved, but if you take out speculation and some pretty significant assumptions, the info available publicly doesn't conclusively indicate his involvement beyond sunday.