Sorry to be graphic but could one person throw a body off the bridge? Do you think he was trying to make it look like suicide? Re my comment about jumping out at the roundabout, just a thought that perhaps she tried to escape,perhaps the car stopped in the roundabout.
I think that's a fair comment about "make it look like suicide", then they brought in the "she was suffering from depression" line.
GBC is a big enough guy, I'd say he'd have no trouble throwing her off a bridge. Which is what I thought when first saw photos of the bridge she was found under, overgrown, isolated area, not much chance of passing motorists seeing her body under that bridge.
There would be a car left at the bridge if someone committed suicide so someone would have had to drive the car there after the fact, which is not the case.