Be careful your home digital assistant doesn't rat on you. In Arkansas, police obtained a search warrant for an Amazon Echo belonging to James Bates in the hopes the device would cough up voice evidence to suggest Bates had strangled his friend in a hot tub.
The Amazon Echo, like other assistants such as Google Home, provides information when people speak a so-called wake word—the wake word is "Alexa" in the case of the Echo—and pose questions like "What's the weather?" or commands like "play 80's music." Such questions are not preserved on the device, but are instead stored on Internet servers controlled by Amazon and Google [fortune-stock symbol="GOOG"}.
In the case of Bates, it's unlikely he asked the device "Alexa, how do I dispose of a body?" But the police in Arkansas reportedly thought that, on the night of the murder, Bates or someone else may have activated the device inadvertently. If they did, any ensuing recordings might help solve the crime.
Get Data Sheet, Fortune’s technology newsletter
Amazon declined to comment on the specifics of the Bates case but spokesperson Kinley Pearsall provided a statement.
"Amazon will not release customer information without a valid and binding legal demand properly served on us. Amazon objects to overbroad or otherwise inappropriate demands as a matter of course," said Pearsall in an email to Fortune.
As it stands, no one has disclosed the voice history of Bates's Echo, which was used to play music the night of the murders, and the odds of it containing a smoking gun are slight.
Nonetheless, the hot tub murder case is intriguing because it raises the question of how and when "always on" devices can be used to testify against us.
The issue is a timely one because a growing fleet of devices under the Internet of things umbrella are appearing in our homes, and many of these devices contain sensors or microphones that can record all of our activities.
From a legal perspective, it's unclear how much of this evidence would be admissible. A defendant, for instance, could challenge it as hearsay or, in some states, as an illegal recording because it took place without their consent.
For now, though, courts have only begun to consider the implications of these devices in criminal trials.
As for Bates, it is ironically a different sort of smart home device that could cook his goose. Per the Information:
court records suggest the device prosecutors got more from wasn’t the Alexa but the home’s smart water meter. It showed that someone used 140 gallons of water between 1 a.m. and 3 a.m. at Mr. Bates’ house, a much heavier than usual amount. Prosecutors allege that was a result of Mr. Bates using a garden hose to spray down the back patio area from the blood.
Bates is currently out on bail awaiting trial next year.
This story was updated to include comment from Amazon.