Like millions of Americans, I've been watching the news of Nancy Guthrie's disappearance with concern—so I was somewhat relieved when the FBI announced they were releasing new footage of a suspect. Finally, the case had something to go on, even if it was only doorbell video of a masked stranger.

When I saw the footage, I assumed this was something the FBI had in their possession since the beginning, and had finally decided to release to the public. But that's not what happened at all. If you have been following this case closely, you may know that law enforcement had previously confirmed that Guthrie's Google Nest camera was disconnected (presumably by the perpetrator), and that she did not have a subscription that would store video either on the doorbell or in the cloud. Yet despite the fact the doorbell should have been a dead end, the FBI has seemingly produced this video out of thin air.

If you have a Google Nest device in or attached to your home, this might give you pause. Sure, it's one thing if law enforcement is able to obtain video from your subscription or from the device itself. But if you don't keep video records on your Nest, it seems it is still possible to retrieve the footage. How did the FBI do this, and what does it mean for the privacy of your Nest devices?

The FBI likely pieced the video together from fragments

The short answer is that we don't really know for sure how the FBI got the footage, but there are a few leads. According to FBI Director Kash Patel, the Google Nest footage was recovered "from residual data located in backend systems." That's pretty vague, though the FBI isn't necessarily known for its transparency_.

According to experts that spoke to NBC News, however, it is possible to obtain data from the "complex infrastructure" of cloud-based cameras, including Google Nest devices. Retired FBI agent Timothy Gallagher told NBC News that Guthrie's Nest camera might have sent images to Google's cloud service, or at least stored data points locally throughout the hardware of the device, even though she wasn't paying for a Nest subscription. The FBI could have obtained the footage from the cloud this way, or pieced together the video from those data points.

Both possibilities track, based on how Nest cameras work without a subscription: While you need to pay Google in order to save video clips from your Nest cameras, some Nest devices record event histories and store them on-device. The third-gen wired Nest Doorbell can save up to 10 seconds of clips, while the first and second-gen wired doorbells can save up to three hours of event history, all without a subscription. They also support live video feeds when motion is detected, which could impact the video data points saved to the device or cloud.

It's entirely possible the subject walking up to the camera triggered the doorbell to save an event history. But since it took the FBI so long to produce the footage, and since the director claims it was obtained from "residual data," my guess is it wasn't readily available in Guthrie's Google Home app. Maybe the event history saved to the cloud, but it wasn't clear where it was located. Maybe it was overwritten, but the FBI was able to build it back up with recovered data points. My guess would learn toward the latter, as authorities did say the camera had been disconnected. Unfortunately, we don't have a definitive answer at this time, even if the theory is sound.

I've reached out to Google for comment, and will update this piece if I hear back.

Should you get rid of your Nest camera over privacy concerns?

Based on what we know, it doesn't really seem like your Nest doorbell or camera is a fourth amendment disaster waiting to happen—but I don't blame anyone for being concerned. After all, if you don't have a Nest subscription, you might have been comforted by the thought that none of your footage was being saved anywhere, meaning law enforcement or other authorities would have nothing to seize if you somehow popped up on their radar. That doesn't necessarily appear to be the case.

That said, without a subscription, you don't have access to a collection of all clips your Nest camera has ever recorded. You might have a limited event history saved, based on motion detection, but that will be limited to three hours of data. Your device might have data points that an organization like the FBI could theoretically use to restore footage, but that's likely true for any camera or smart doorbell system—not just Nest.

Also, this is not a Ring situation—Google hasn't partnered with organizations like Flock to help law enforcement request footage from users. Nest also lacks Ring's "Search Party" feature, which can turn a neighborhood into a kind of surveillance state, and probably not just to search for lost dogs. I'm not dismissing every security and privacy concern, of course: By putting a commercially-available smart camera on your front door, you are placing your data in the hands of companies like Google or Amazon. If you want to eliminate the risk of the FBI obtaining your doorbell footage, you simply can't have a doorbell with a camera. But barring a warrant, or a Nancy Guthrie-level situation, the chances of your Nest doorbell footage actually being used against you seem rather slim.