Amazon has considered adding facial recognition technology to its Ring doorbell cameras, according to a letter to a U.S. senator defending its video-sharing partnerships with police.

The company told Sen. Ed Markey that facial recognition is a “contemplated, but unreleased feature” of its home security cameras but that there are no plans to coordinate that feature with its law enforcement partnerships.

Markey wrote to Amazon CEO Jeff Bezos in September raising privacy and civil liberty concerns about Ring’s video-sharing agreements with police departments across the country. The company encourages police to tap into Ring’s Neighbors app, a forum for residents to share videos of suspicious activity captured by their home security cameras.

The Massachusetts Democrat also expressed alarm that Ring may be pursuing face-scanning technology after a patent application showed the company is exploring a system that could flag certain people as suspicious and automatically alert police.

Markey released Amazon’s responses Tuesday.

Amazon’s initial response to Markey said Ring doesn’t currently offer facial recognition. Then Markey sent another letter to Bezos asking why it’s mentioned in Ring’s privacy policy. In a Nov. 1 follow-up, Amazon’s vice president of public policy, Brian Huseman, said that the company frequently innovates based on customer demand and that facial recognition is an increasingly common feature in cameras made by competitors such as Google’s Nest division.