If that smart new home device in your bedroom is voice activated, then it's always listening.

That also means it's probably often recording, and sending information to the cloud.

So what happens when a judge or prosecutor thinks some of those recordings might be pertinent to a case?

Or perhaps they want to check information from your Fitbit to see if you were near a crime scene?

It might sound dramatic, but experts believe data collected from our devices will increasingly find its way into Australian courts.

Out of the cloud and into the courts

Michael Legg, a law professor at the University of New South Wales, expects personal data will be sought out as digital evidence.

"The only real barrier is the creativity of the lawyers and then possibly the cost to be able to access it," he says.

Professor Legg likens it to the emergent trend of social media posts being used in the courts as proof of a defendant's guilt or innocence.

"Social media is a good example — it wasn't being used at all, and now it has become quite common, particularly in some areas of law, like personal injury or family law," he says.

While companies like Google and Amazon will likely be resistant to releasing information recorded by their devices, under a court subpoena they may have no choice.

An Echo device, which connects with Amazon's Alexa voice service. ( Supplied: Amazon.com )

"It may be that if they need to comply with the law or a legal process, which is what a subpoena would be, you effectively understand that the law requires them to disclose it and therefore they will," Professor Legg says.

"As soon as you have a case where stakes are high and there is a fight for what can be loosely termed an informational advantage, people will go to all sorts of lengths to be able to obtain any sort of information that demonstrates that their case is more likely to have occurred than not."

What sort of information could be used?

This week Apple launched their latest entry into the smart device market — the HomePod — accompanied by a slick Spike Jonze-directed commercial. In the ad, an office worker (played by musician FKA Twigs) fights through a dreary commute home.

This content cannot be displayed.View original

Looking defeated as she slumps into her small apartment, she looks over at her Apple HomePod and instructs "Hey Siri, play me something I'd like", and an up-tempo song plays.

But what if the office worker had let her day get the better of her and asked — jokingly or otherwise — "hey Siri, how could I kill my co-workers?"

It's benign enough in isolation, but a recording of that question is still sent back and stored in the cloud. If something was to happen to one of her colleagues, that recording — stripped of context — could be used as compelling evidence against her.

Less extreme situations might involve using information recorded by a home or personal device to prove — or disprove — an individual was present in a location.



"There have been a couple of interesting cases in America where, for example, a gentleman asserted that he was woken up and his home was on fire and he had rushed out," Bond University's Kate Mathews-Hunt says.

"In actual fact his Fitbit data showed that he had been engaged in heavy labour, which I think included removing quite a lot of things out of his home, and so his insurance claim was effectively impugned on that basis, that his story didn't hang together.

"So it's an incredibly interesting area, but it is also problematic."

Amazon Echo helps clear US murder charge

Late last year, a United States judge dismissed a murder charge based in-part on recordings captured by an Amazon Echo home speaker.

Victor Collins was found dead in a hot tub at the home of friend James Bates after a night of booze and football.

James Bates was cleared of murder charges of his friend Victor Collins ( Supplied: 5 News )

Police charged Mr Bates with murder. He pleaded not guilty, maintaining he had gone upstairs to bed around midnight, having set up bedding for Mr Collins and another friend downstairs.

During the case, Arkansas police requested recordings from Mr Bates' Amazon Echo.

Amazon themselves initially rejected the request, but the defence attorney for Mr Bates, high-profile lawyer Kathleen Zellner, ultimately supplied the recordings to the court.

"Fairly soon after I came into the case I had a meeting with my client. He had accessed the information that was on the Amazon Echo. I listened to the recording [and] hired experts because I felt like the case was flawed," Ms Zellner tells The Law Report.

"There was nothing incriminating on the recording.

"I told my client that I wanted to disclose the information because if we did not, we were going to end up going to the US Supreme Court on this issue. That would be foolish because I had evidence that would exonerate him and I could have the murder charges dropped.

"So I notified Amazon and I notified the prosecutor that we were disclosing the information."

Curiously, another a piece of recorded personal data was also used to help clear Mr Bates.

"Police believed that [Mr Bates] had gotten back up, they were trying to construe that he had gone back out and committed this murder," Ms Kellner says.

"It turns out that Mr Bates on his iPhone had the 'steps app' that records steps that you take, and the steps app showed that once he went to bed, he never moved again until he got up in the morning."

Is the truth actually being recorded?

Fitbits track an individual's wellness, as well as their location. ( Supplied: New Deal Design )

While it might be increasingly possible to access recordings made by home devices, that doesn't necessarily mean they will provide uniformly reliable evidence.

"How do we know that this information that is being put forward as being objective, and reliable and demonstrating effectively a contravention of the law and guilt, can be relied on?" Professor Legg says.

"How do we actually make sure that the readings are in fact correct?"

Sorry, this audio has expired Hear the full episode

Even though her client was exonerated with help from a home device recording, Ms Zellner is equally apprehensive about the way such recordings could be misused.

"You know how people with these devices will ask questions and they'll be kidding or joking, and I'm sure people have asked it questions like, 'How do I hide a body? How do I dispose of a body?'" she says.

"I imagine what will happen is that there will be a case in which the police seek to get recordings and there will be conversation that is ambiguous on the recordings that the prosecution would try to construe as some admission of murder.

"It's definitely going to be at the forefront I think in a lot of criminal cases, probably all over the world but certainly in the United States."