Perhaps they told him yes or no to his question. I don't know. I highly doubt that they gace him much information concerning the vehicle owner,address ect.
I would think they would have to run the check to confirm whether or not the vehicle was wanted for being involved in a robbery in the first place in order to confirm, no? If so then I would think that checking at all based on someone calling in would be a violation.
Assuming the OP was truthful, they either checked for it based on his calling in, or didn't check and just made something up.
Something just doesn't seem right with the whole story to me. I'm not sure what, but something doesn't sound right. Maybe it's just my suspicious nature.