Well worth a read this morning if you’re interested in the intersection of government, law enforcement and privacy and civil liberties issues: A detailed Washington Post report on what is effectively becoming a national database of individual photos available for law enforcement use.

The faces of more than 120 million people are in searchable photo databases that state officials assembled to prevent driver’s-license fraud but that increasingly are used by police to identify suspects, accomplices and even innocent bystanders in a wide range of criminal investigations . . .

The increasingly widespread deployment of the technology in the United States has helped police find murderers, bank robbers and drug dealers, many of whom leave behind images on surveillance videos or social-media sites that can be compared against official photo databases.

But law enforcement use of such facial searches is blurring the traditional boundaries between criminal and non-criminal databases, putting images of people never arrested in what amount to perpetual digital lineups. The most advanced systems allow police to run searches from laptop computers in their patrol cars and offer access to the FBI and other federal authorities.

Click on the image below to visit an interactive version on the Post site, which gives you information by state as you hover your cursor.