This is your answer. The 10 hits were on a national database.:
Ten times, authorities thought the car warranted enough suspicion that they ran its license-plate number through a national police database, sources said. Each time, however, they let the driver go after finding no record that it had been stolen or that its occupants were wanted for any crimes.
I am far from a database expert but I think most databases could kick out "most often searched for" if queried. How hard can that be for a computer to do? I doubt that it was done. It may have been suggested but it was never done. What was needed was less racial profiling of white guy shooters & white vans and better computer work
Not disparaging your quote, but when MD police contact their dispatcher with a license plate, the resultant feedback sounds like it is coming from the MD DMV (from other information that they sometimes provide). I guess you are saying the MD system automatically queries the national system on out of state plates, and the feds could have easily run a search for multiple hits in a certain geographic area?