I Think I'm Being Watched With a Hidden Smoke Alarm Camera

Weeks ago, I noticed movement within the smoke detector LEDs when the lights were out. After moving, I no longer saw any movement from the detector. To confirm it wasn’t just my eyes playing tricks, I had someone else check, and they saw it too. How can I determine if this is a hidden camera? Has anyone experienced an invasion of privacy in this way? What should I do? Are there other subs where I can post this?

I checked the unit but could only access the battery compartment, not the internal section. The detector is hardwired to the ceiling, so I can’t remove it myself.