P.S. I am operating on the assumption that they did not cross the river to NJ. Their truck would certainly stand out on a secrity camera. What I have read suggests the LE assumes they did not cross the bridge. What about EAZY-PASS (or what ever it is call out there)? Richard commuted every day to NJ so he must have had one. Is there a toll gate eastbound on those bridges?.That should settle the issue.
You pay tolls going into PA and not into NJ (you pay westbound). The bridges are operated by a joint Delaware River Commission. You used to pay both ways (even using tokens!), but now you just pay double going into PA. It's a lot like coming and going over the GW bridge from NJ to NYC.... the running joke is that no matter where you are, you have to pay to get out of Jersey.
There are smaller bridges however (like in the Trenton area) that allow you to cross either way for free.