So here's the plan: you snag the bridge and I will sell it

Imagine the scene. A couple buddies in need of a few bucks. They know they can turn in steel at the scrap yard. So they go collect some. Well...some might be an understatement. 200 tons to be more or less in the ball park. So when a couple of bridges turned up missing, the police had a fairly good idea of where to look....

You have to wonder how that conversation went. How do you get from, "I need a few bucks" to "let's steel two fully constructed bridges". What, did they think nobody would notice?