Authorities in New Mexico, US have reported that a 'smart home device' was triggered by statements during an alleged domestic dispute which was turning violent and called 911.

Police say that when they arrived on the scene in response to the call, they found Eduardo Barros threatening his girlfriend with a firearm. They managed to de-escalate the situation and were able to remove the woman and her daughter to safety.

According to ABC News, the couple were house-sitting at a home with a smart speaker device wired up to the surround system. Barros allegedly pulled a gun on his girlfriend and asked "did you call the sheriff's?"

The obediently listening smart speaker interpreted this as a request and promptly called 911. Even though nobody spoke to the dispatcher, the commotion could be heard over the phone, so police arrived to investigate.

"The unexpected use of this new technology to contact emergency services has possibly helped save a life," local sheriff Manuel Gonzales III told ABC News.

"This amazing technology definitely helped save a mother and her child from a very violent situation."

After a lengthy stand-off, a crisis negotiation team and SWAT officers were eventually able to take Barros into custody.

Court records show that Barros now faces several charges, including aggravated battery against a household member. He had his first hearing on July 5.

We don't know which of the various smart home devices on the market was responsible for this valiant rescue - earlier versions of the report stated it was a Google Home speaker, but have since been corrected to an unidentified device.

But it's not the first time one of these gadgets has been involved in police investigations. Late last year we reported that Alexa, the software running on Amazon's smart speaker Echo, may have witnessed a murder.

These smart speakers typically only react to sounds when triggered with a specific activation word, such as 'OK Google' or 'Amazon'. But even with that being the case, Amazon has since agreed to hand over the data to prosecutors as the case continues.

And it's all well and good when a smart device does something helpful as in this alleged domestic violence case, but the very fact it called the cops is a reminder that these speakers are just sitting thereā€¦ constantly listening.

For some users, that's an uncomfortable level of surveillance, and a lot of smart devices are also potentially vulnerable to cyber attacks.

In the end, this technology is so fresh, we're still figuring out exactly how much privacy we're giving up when we rig out our homes with the 'Internet of Things'.