Nancy Guthrie missing case: Google to the rescue? Tech giant's key role in recovery of surveillance video explained

Hours after the FBI on Tuesday released surveillance footage from the night of Nancy Guthrie's disappearance, one person was detained in Arizona, while police commenced a search of a property in Rio Rico.

The FBI's release of surveillance footage on Tuesday came after days of no major breakthroughs, and it may not have been possible without the expertise of tech giant Google, reports indicate.

At the time Pima County Sheriff Chris Nanos had said that there was no video footage as the 84-year-old "had no subscription" to Google Home, which keeps videos recorded from Nest cameras in the search giant's cloud.

This proved to be a major roadblock for investigations, with authorities having no leads on or footage of the suspects.

So dire was the situation that investigators, understanding the technical complexity of recovering footage without backups, did not even know whether extraction would be possible.

This is where Google stepped in, with CNN, citing a person familiar with the investigation, reporting that it came down to the search giant's technical expertise.

In essence, even if the data is deleted from Google’s systems, it could still exist somewhere and be recoverable because even files slated for deletion can exist until they are overwritten by fresh data.

But why is this the case? Adam Malone, a former cyber-focused FBI special agent and currently the top cyber crisis expert at cybersecurity advisory firm Kroll, told the news outlet that videos recorded by cloud-based systems go through "layers and layers" of components, this data could through hundreds of thousands of severs and systems distributed globally. This, Malone explained, raises the chances of data being left behind.

“A delete function is just telling the file system to ignore that data and feel free to use that space on the hard drive for new data …. so until it’s actually used again, that old data is still recoverable,” CNN quoted Nick Barreiro, an audio-video forensic analyst and the founder of Principle Forensics, as saying.

“I’ve had cases where I could go back months or even years and find little fragments of video files that were still on the hard drive,” the digital forensics expert added, speaking from experience.

FBI Director Kash Patel had also hinted at the same when, while releasing the footage, he announced that some video had been recovered "from residual data located in backend systems".

“They would have all looked at their development pipelines to say, ‘Hey, do we process any data? Do we have any historical data that’s still sitting here waiting to be purged?” Malone explained to CNN, commenting on Google's likely approach.

It is this data that Google technicians recovered, a process so complex that it took 10 days.

Shortly after the video's release, former prosecutor and current criminal defence lawyer John W Day told New York Post, “It [the breakthrough] gives us some insight to what Google is capable of”.

“Even without paid subscription, there is a way to go to some data center and spend a lot of time and effort to try to find that particular camera, at that particular time without a subscription. You can only imagine how difficult that was if it took 10 days to get there," Day explained.

The company, however, is yet to comment.