MS was nothing more than a low level street dealer, he got his stuff from other low level dealers, there are no high level dealers in this mix for any of the witnesses to fear, they are nervous because they are in a court of law testifying at a murder trial, anyone in that position would be...
DM guilty of 1st Degree
MS guilty 2nd Degree only as a technicality, I believe he was just as involved and new of the plan but I am not sure if there is enough evidence to prove premeditation on his part. Unless MM knows something that has yet to be revealed.