More than 450 Amazon employees have now signed a letter originally addressed to CEO Jeff Bezos and other senior executives in June asking Amazon Web Services to stop selling its Rekognition image and video cloud service to police departments.

An anonymous employee posted an essay on Medium Tuesday outlining the group’s case, which also calls on AWS to boot Palantir, the secretive data analysis company, from its services. Medium editors said they verified the author’s identity and authenticity of the post, and also published their own interview with the employee.

“Companies like ours should not be in the business of facilitating authoritarian surveillance. Not now, not ever,” wrote the anonymous author, who cited employee protests at Google and Microsoft over their work with government and military contracts as inspiration. Rekognition, which allows users to analyze images and video for the purposes of facial recognition, has been under fire for months after two police departments in Oregon and Florida talked about the work they were doing with the service.

Amazon employs 575,700 people, so it’s a little hard to tell if this sentiment has a lot of traction inside the company or not. But it seems pretty clear that this recent surge in employee dissatisfaction across the tech world when it comes to working with government customers is relatively new, given that AWS has been working with the Central Intelligence Agency since 2013 and other tech companies have long courted the bulging budgets of big government.

It’s not hard to say why.