It may be that many of those arrested on the basis of questionable face recognition searches did in fact commit the crime of which they were accused. But the possibility that they didn’t—that the face recognition system identified the wrong person—looms large in the absence of additional, independent police investigation and sufficient access to the evidence by the defense. This is risky, and the consequences will be borne by people investigated, arrested, and charged for crimes they didn’t commit.

A slide from NYPD FIS describing “Removal of Facial Expression” technique.

In early 2018, Google rolled out "Art Selfie" — an app designed to match a user's photo to a famous painting lookalike using face recognition.12 The result is an often-humorous photo pairing and an opportunity to learn more about art. Less humorous is the fact that some police departments do the same thing when looking for criminal suspects, just in reverse—submitting art in an attempt to identify real people.

The stakes are too high in criminal investigations to rely on unreliable—or wrong—inputs.

On the left: a slide from the NYPD FIS describing its "celebrity comparison" technique. On the right, a photo of Woody Harrelson.