A Kansas trooper saw Esquivel-Rios driving a van down the highway. The van was displaying a Colorado temp tag, and the trooper called the tag into dispatch to have it checked against all the various databases that we use for that sort of thing. The dispatcher informed the trooper that there was no record found for the tag, and that Colorado temp tags usually have no record. Based solely on the information that there was no record found, the trooper stopped the van. During the traffic stop, he received consent to search the van and found a hidden compartment with a lot of meth.
Esquivel-Rios was subsequently convicted of federal drug charges. At the trial (and in his appeal), he argued that the stop was unreasonable and everything found as a result of the stop should be suppressed.
The trial court denied his motion to suppress, and the Tenth Circuit sort of decided not to decide. The Tenth observed that they and other courts have upheld stops based on there being no record of a plate. The idea behind that is that when a government database for license plates doesn't contain information about a particular license plate being used, it "raises a non-trivial possibility that the tag wasn't lawfully issued in the first place but falsified in some way." So ordinarily a stop based solely on information from a database is good to go. The problem is that in this case, the evidence suggests that the problem was likely to be with the database.
When the dispatch said that records of Colorado temp tags usually don't come back, this suggests that there's some explanation other than wrongdoing on Esquivel-Rios' part. Maybe Colorado doesn't put temp tags into a database (until recently, Colorado didn't). Maybe there's some other bug between the Colorado database and the Kansas one. Or maybe the tag is suspicious and there's just a lot of fake Colorado temp tags in Kansas. The trial court didn't really look into it.
The Tenth found that the "no record" issue could go either way. It could still meet the standard or reasonable suspicion, or it could fall far short of it. It all depends on facts which weren't explored by the trial court because the trial court just ignored Esquivel-Rios' challenges to the database's reliability. So rather than decide this case, the Tenth sent it back to the trial court to more fully develop the record as to what the dispatcher meant by "usually," and as to what the trooper's previous experience with Colorado temporary tags has been.
I bet the dispatcher wishes he could take that remark back now that it's getting picked apart in court.