"We write to reiterate our concerns about Amazon's facial recognition technology, Rekognition, and request additional information about this product and your decision to make it available to law enforcement agencies," they wrote. "Regrettably, despite asking you a series of questions on this subject and requesting specific information in letters sent to you on July 26, 2018 and July 27, 2018, your company has failed to provide sufficient answers."

Amazon has faced a fair amount of pushback on its facial recognition policy and its decision to sell it to law enforcement groups. The ACLU, Amazon investors and company employees have expressed their concern over the issue, while two other members of Congress -- Representatives Keith Ellison (D-MN) and Emanuel Cleaver (D-MO) -- sent Bezos a letter in May seeking more information about Rekognition. In October, Amazon generated more unease when reports surfaced that it had pitched its facial recognition technology to ICE.

In its initial response, Amazon said that it had an acceptable use policy "that prohibits the use of our services for '[a]ny activities that are illegal, that violate the rights of others or that may be harmful to others.'" It added that any group using its technology is required to abide by its terms and conditions, which also mandates compliance with relevant laws, including COPPA, the Children's Online Privacy Protection Act.

Of the seven questions the lawmakers sent Amazon the first time around, four were reiterated in their most recent letter. Those questions include queries on assessments of bias, whether protections are built into Rekognition to protect the rights of innocent citizens, if Amazon conducts audits of its law enforcement customers and whether the technology has been integrated with body cam technology. Along with Markey and Gutiérrez, six additional lawmakers -- Representatives Jimmy Gomez (D-CA), Jan Schakowsky (D-IL), Pramila Jayapal (D-WA), Ro Khanna (D-CA), Judy Chu (D-CA) and John Lewis (D-GA) -- also signed onto the letter this time around. They've requested a response by December 13th.