Well I am still hearing a lot of DM this and DM that. It was DM's phone. DM called. DM's toolkit, DM's hangar, DM's incinerator. Keys in DM's car.
MS was just DM's right hand man, and could claim that because DM set everything up and used all of his own resources, that MS wasn't expecting a murder and the rest of it. I.e., MS was more an accessory after the fact, helping to dispose of the evidence, rather than a participant in the plan to murder. MS could claim it just got dropped on him and he wasn't expecting DM to kill.