Editors' pick: Originally published Dec. 29.

Amazon (AMZN) - Get Report has refused to share with Arkansas law enforcement information gathered from its popular Echo device in a situation that could become increasingly common as voice-activated devices proliferate.

Police in Bentonville, Ark. have issued search warrants demanding access to data after a man was charged with murdering another man in November 2015 within earshot of an Echo device, according to the Information.

"Amazon will not release customer information without a valid and binding legal demand properly served on us," a spokesperson for the Seattle-based company told TheStreet. "Amazon objects to overbroad or otherwise inappropriate demands as a matter of course." The company said it would not give comment on specific cases, however.

The case highlights the tension between law enforcement groups and device makers who want to assuage customers' concerns about privacy. Apple (AAPL) - Get Reporthas been involved in the most high-profile cases involving law enforcement requests to gain access to data stores on devices, most notably one from the FBI to obtain information about the gunman the 2015 San Bernardino shooting.

Apple refused to accede to the FBI's request and the agency wound up hacking into the gunman's phone by other means. Many other technology giants, including Alphabet's (GOOGL) - Get Report Google, Facebook (FB) - Get Report and Yahoo! (YHOO) , routinely receive requests for information on users from the police and intelligence agencies.

Amazon's voice-activated technology can only be turned on by asking it a question preceded by its name, Alexa. The Echo only records and stores voice data when it's been given a command, but in order to hear a user say its name to issue a command in the first place, Alexa must be listening to its surroundings at all times.

The Echo does come with a "mute" button to stop the device from listening in, but otherwise its ear is always open. The question, however, is how much of that data is being kept by Amazon.

Apple, Alphabet and Facebook are holdings in Jim Cramer'sAction Alerts PLUS Charitable Trust Portfolio. Want to be alerted before Cramer buys or sells AAPL, GOOGL or FB? Learn more now.

"In our homes, there are all sorts of conversations that are going on and are meant to be personal and private," Lynn Terwoerds, executive director of the Executive Women's Forum on Information Security and Risk Management, told USA Today recently.

In the case of James Bates' alleged murder of Victor Collins in November 2015, private conversations heard by Bates' Alexa device could be used against him if authorities are able to access that data. The murder case will go to trial in early 2017, and could give more insight into what voice-activated assistants like Alexa hear --- and what data their creators record and keep -- when they're inside our homes.

Amazon's Echo isn't the only device now tuned to scan all our conversations for key phrases. Apple's iPhone has Siri, while Microsoft (MSFT) - Get Report has Cortana for several of its operating systems,. Google also released its own Echo-like smart speaker device, the Google Home, earlier this year with a voice-activated assistant simply addressed as "Google."

Standalone voice-assisted devices aren't nearly as popular yet as the iPhone or other smartphones. But with more and more names jumping into voice activation, the devices are bound to get more popular, too.

Amazon announced on Tuesday that its line of Echo devices were the best-sellers of the holiday season on the site, with "millions" of devices sold. Sales were up more than nine times over last year's holiday season, the e-commerce company said.

And as these devices become more common, they could raise more concerns about what exactly is being recorded and what can and can't be revealed to law enforcement.