TUCSON (KVOA) - For most of us, our smartphone is a constant companion.
It is for criminals, too. Ultimately, it may be the key to putting them behind bars.
However, the technology that could be used to help put those criminals away must overcome legal obstacles.
Smartphones keep us connected to our family, friends, and to the rest of the world. These devices are also equipped with GPS and other technology that can track the exact location of the person using it. That technology is now helping lead police right to their suspect.
"People need to understand that when you carry your cellphone on you, you are being tracked at all times," Mark Rumold, lead attorney with the Electronic Frontier Foundation told the News 4 Tucson Investigators.
The inherent ability to track cell phones, along with the people who may be using them, is what Geo-fence warrants are all about.
The warrants are a sort of a 'digital dragnet' in which Google provides detectives information regarding all location-enabled smartphones that were present within a specific area, during a specific time-frame.
"Imagine this - your child is kidnapped off the street one night. The police file a search warrant to know whose cell phone was being used at that precise time and that precise location. That can save a life," Frank Figliuzzi, a former FBI Assistant Director, told the News 4 Tucson Investigators.
Figliuzzi, who recently authored The FBI Way: Inside the Bureau's Code of Excellence, tells the News 4 Tucson Investigators, Geo-fence warrants can serve as a powerful crime-fighting tool. However, he adds, it is also important they are used cautiously during an investigation.
"We can do this safely. It solves crimes, it's a tremendous law enforcement tool. We just need to get it right," Figliuzzi told the News 4 Tucson Investigators.
In reviewing Pima County Superior Court documents, the News 4 Tucson Investigators uncovered at least three Geo-fence warrants filed by TPD detectives. Those detectives are now working to solve crimes ranging from armed robbery to murder.
Citing ongoing investigations, a TPD Public Information Officer did not want to go on-camera to talk about those Geo-fence warrants, or how often they are being used to try to solve crimes.
Geo-fence warrants are not without their opponents.
Groups including the American Civil Liberties Union and the Electronic Frontier Foundation fear they could be overly-broad, and potentially be misused.
"These warrants essentially compel Google to go through the location information of tens of millions of its users," Rumold told the News 4 Tucson Investigators.
That said, a judge must sign-off on the Geo-fence warrant, based on a showing of probable cause by the detective who requests it. Further, the information Google returns to law enforcement doesn't contain names or phone numbers, but rather, a unique identifier. Detectives must then go back to a judge, and ask for a second warrant to compel Google to provide additional information about who actually may have been using the phone at the time and place a crime occurred.
This, according to Figliuzzi, is one important step in trying to balance crime fighting, with preserving constitutional rights.
"We need to narrow this down, get rules and regulations around this, and, it's possible that state legislatures, and even the U.S. Congress will need to address this" Figliuzzi concluded.
The number of Geo-fence warrants continues to surge, with Google receiving about 180 law enforcement requests for location history information each week.
Geo-fence warrants could also face additional legal challenges. According to the Electronic Frontier Foundation, recent federal court rulings held that the warrants violate requirements under the Fourth Amendment.