Yes, per the photos posted upthread showing the Nest mount beside the door, the camera was battery operated. Also note, the traditional doorbell is still intact in the photo. The battery operated Nest uses wifi, not bluetooth, and must be on-network to upload videos to the cloud. If for any reason wifi connection is lost, it will try to reconnect, but only to the network for which it has the password. SOME Nest cameras (see link) have local storage capacity to store videos for a relatively short time (like an hour) while wifi is lost and then will upload that to the cloud once the connection is restored. In this case, we know the camera was removed from the mount, source photos upthread. We don't know how it was removed. AB reported cameras were smashed, although others have indicated the camera was/was not recovered. If the camera was smashed, obviously the recording would cease. If just removed and set aside, it could continue recording. Another factor is how the camera was actually setup. Most record only after motion is detected, and many have zones established for motion detection so that things like passing cars are not always setting off a motion alarm. No information given AFAIK on the particular Nest model involved, clear statement on means it was 'disconnected', how it was setup, etc.
Important: Your camera needs to be connected to both Wi-Fi and the Nest service to upload video to the cloud. All Google Nest cameras and doorbells can securely upload and save video in the cloud. On
support.google.com