Just going to throw these out as I review them in case they spark some ideas we haven't considered before.
Forensic Files Season 2, episode 2. Son murders parents and uses both of their cars to dispose of the evidence. Mom's for cleanup, dad's for bodies. LE catches him by testing soil on mudflaps of dad's car which leads to their final resting place.
Season 4, Episode 4: Husband arrested for wife's murder and actually admits to the crime but is exonerated by a partial handprint of another criminal.
Season 5 episode 10- murder of various children in nursery using a paralyzing chemical called suxamethonium chloride. Now, this gave me pause and I started googling around. This drug has been known as "the perfect murder weapon," is used in wild animal control and is also used in dart guns. It metabolizes super quickly so it is very difficult to trace in human tissues. Can also be placed into drinks.
I'm not sure of the rules regarding what I can link but I've found some VERY interesting articles on pubmed about murders using this chemical compound.
If Barry has listened to all of these then I do not think he has used a family vehicle to dispose of Suzanne's body.
The partial hand print is interesting given Barry's Lawyers repeated insistence that the partial DNA in Suzanne's car has not been properly investigated.
It will be ironic if he soon will feature on forensic files