Exactly. There was a frozen body in that boot, so work back from there.
Go on then.
We have MM's DNA in bodily fluids in 5a behind the couch (statistically significant / almost certainly hers)
We have a blood dog alert in the same place where the fluids were found.
We have MM who is missing and no other tenants have reported people dying / going missing in there / from there.
We have a long gap in days prior to the car being hired.
We have GM pissing about with refrigration devices that don't belong to him.
We have the hire history of the vehicle.
We have fairly solid eye witnesses stating the boot was left open for prolonged periods, again, on of the very few facts corroborated by the McC's themselves (funny how they continually come up with a story when faced with solid eye witness statements, but failed to mention any of it prior to, despite being potentially significant in the search for their daughter).
We have bodily fluids (mixed sample) in the boot of the car.
We have a cadaver dog alerting to said car and the car key, oddly enough.