Yes, based on the charges, it is very evident MS was the one who did the actual killing, because DM was charged with forcible confinement, we know that TB did not make it to another location, in Canada if you confine someone forcible and they die on yoU, a first degree murder charge will be laid. Because DM was charged with theft, we know that he was driving.
Now, if the charges were kidnapping, TB would of had to make it to another location before death. So because of the charges, we know who did what.
If anyone followed the tori stafford case, Michael Raffferty did not actually tori but because he kidnapped her, it would be first degree murder charge ieven if he actually did not kill her.
Points to consider, TB was not kidnapped, therefore he was killed inside the car.
Tori Staffored was unlawfully confined, kidnapped and first degree murder charges were laid against MR
Laws in Canada are different than in US but still similar.