Unscientific. The best facial recognition is accurate 98%-99.9% of the time. There are minor known problems with blacks (~2% worse), bad lighting, bad cameras, but big problems with small databases to compare against. There are yearly vendor tests and challenges. E.g https://en.wikipedia.org/wiki/Face_Recognition_Grand_Challen... Latest winners are all in the 99.9% ballpark, not 4%.

If the Detroit police has no faces to compare against and the image quality is crap, it's certain that their success rate cannot be much better than 10%.