Seven members of the House of Representatives and one United States senator have now sent a second letter to Amazon's CEO, asking for more clarification about the company's use of facial-recognition technology.

Although two House members in the group sent a similar letter to CEO Jeff Bezos back in July, the larger group now says that Amazon "failed to provide sufficient answers" about its commercial facial-recognition program, known as Rekognition. Prior to the July letter, the American Civil Liberties Union used the service in a demonstration of its inadequacy—the service falsely matched 28 members of Congress with mugshots.

The new letter, issued on Thursday, was signed by Sen. Edward Markey (D-Mass.), Rep. Jimmy Gomez (D-Calif.), and others. The document states that the legislators have "serious concerns that this type of product has significant accuracy issues, places disproportionate burdens on communities of color, and could stifle Americans' willingness to exercise their First Amendment rights in public."

The lawmakers continued:

Does Amazon build protections into the Rekognition system to protect the privacy rights of innocent Americans caught up in either the biometric databases used by law enforcement for comparison, or in the data law enforcement uses to search those databases? Does Amazon Rekognition contain a mechanism for automatically deleting unused biometric data?

Amazon did not immediately respond to Ars' request for comment.