At that point it doesn't matter. The cops don't do legal decisions. Once the warrant goes out, that is what they execute.
Then someone screwed the pooch earlier. They shouldn't have sworn out the warrant without sufficient proof from the dealership that a crime was committed.
I don't know exactly what the employee told them, but if he came in with a claim that the someone paid $5,600 less than they were supposed to, then the police should have investigated the circumstances more thoroughly. They should have seen the signed contract, and told the employee to go home.
Of course, if the employee simply said that the vehicle was stolen, then that was an out-and-out lie. He would have to fabricate a complete story that didn't hint there was any misunderstanding -- or the police should have have investigated further.
My point is there was plenty of opportunity for the police to figure out this was simply a dispute over the selling price, if the employee even hinted that it was something besides a guy that took a car for a test drive and didn't return it. Once any paperwork was signed, it became a civil dispute, not a criminal one.
At that point it doesn't matter. The cops don't do legal decisions. Once the warrant goes out, that is what they execute.
Not long ago, having your legal contract for your property to show the law was a good idea.