Amazon is kicking off its third annual Prime Day by slashing the cost of an Amazon Echo, cutting 50 percent off the price tag, and selling the Echo for only $89.99. Google is competing by cutting $64 from the price tag for a Google Home and Chromecast bundle, selling the two for $99.99. So, if you\u2019ve been wanting to get a smart assistant for your home or get a jump-start on Christmas shopping, now is a good time for it.However, owning an always-listening smart device cuts both ways; it could be used to save a life and the data from the device also could be used by police for investigations.Smart home device calls the policeA smart device is being credited for potentially saving a life when it misheard a command and called the cops.Eduardo Barros, his girlfriend and her daughter were house-sitting near Albuquerque, New Mexico, on July 2. KRQE reported that after his girlfriend got a text message, Barros accused her of cheating on him. He allegedly hit and kicked her and then got a gun and threatened to kill her. He asked her, \u201cDid you call the sheriffs?\u201dShe hadn\u2019t, but a smart home device had. The\u00a0always-on microphones in the device, which was hooked up to a surround sound system, heard what\u00a0Barros said and took it as the command \u201ccall the sheriffs.\u201d It did.Although Google Home was widely reported to be the smart device that called the cops, ABC News took out any reference to Google Home, adding, \u201cAn earlier version named a smart home device that was not the type found in the home and credited by police with calling 911.\u201dIt\u2019s unclear what the big secret is, what smart home device called the cops, but it led to police, a SWAT team and a crisis negotiation team showing up at the house. Police were able to take the girlfriend and the daughter out of the house. It reportedly took several hours before the cops were able to take Barros into custody.Court records show Barros was charged with 14 counts: 12 counts of aggravated battery against a household member (deadly weapon), one count of possession of a firearm and one count of false imprisonment.\u201cThe unexpected use of this new technology to contact emergency services has possibly helped save a life,\u201d Bernalillo County Sheriff Department spokesperson Felicia Romero told ABC. \u201cThis amazing technology definitely helped save a mother and her child from a very violent situation.\u201dPrivacy concerns with IoT devices\u00a0This isn\u2019t the first time police have turned to data provided by IoT devices. Police in Arkansas previously used data from an Amazon Echo for a murder investigation and data from a connected water meter in another murder investigation. Police in Ohio used data from a pacemaker to charge a man with arson and insurance fraud.Many people already enjoy the hands-free convenience of giving voice commands to smart assistants. Amazon, for example, offers special Prime Day shopping deals exclusively for Alexa users who take advantage of voice shopping.It\u2019s too soon to know what will happen, but Amazon offers an opt-in \u201cDrop In\u201d feature for its devices. For example, Amazon\u2019s new Echo Show, which comes with a touchscreen and camera, allows an Echo Show user to \u201cdrop in\u201d on another. If the person receiving the \u201cdrop in\u201d doesn\u2019t decline the call within 10 seconds of hearing the \u201cdrop in\u201d chime, the person making the call can see and hear into your home via your Echo Show. It\u2019s a feature that has raised many security and privacy questions, but if it follows the line of other smart devices, police will eventually turn to that data during investigations.