It was her Fitbit that gave him away.

In December 2015, Connie Dabate was shot dead in her Connecticut home. When police questioned her husband, Richard, he said that a masked intruder had broken in and attacked her. But the Fitbit she wore on her waistband told a different story. The data it had collected showed that she’d walked 1,217 feet around the house in the hour after Richard said she’d been killed. That information called his story into question and led prosecutors to charge him with murder in April.

It was her Fitbit that gave him away.

In December 2015, Connie Dabate was shot dead in her Connecticut home. The police questioned her husband, Richard. He said that a masked intruder had broken in and attacked her. But the Fitbit she wore on her waistband told a different story. The data it had collected showed that she’d walked 1,217 feet around the house in the hour after Richard said she’d been killed. That information called his story into question and led prosecutors to charge him with murder in April.

Richard Dabate is still awaiting trial, but the case and others like it are raising questions about the nature of privacy in the digital age. Americans are increasingly relying on high-tech gadgets to improve their quality of life: internet-connected security systems, fitness trackers like the Fitbit, smartphones, and personal assistants like Apple’s Siri or Amazon’s Echo, which is also known as Alexa.

But police are beginning to see these devices as something else entirely: evidence gatherers and silent witnesses that continually collect and store data about us whether or not we realize it. 

“It is definitely something we are going to see more of in the future,” says police detective Christopher Jones of East Lampeter Township, Pennsylvania. “As people continue to provide more and more personal information through technology, they have to understand we are obligated to find the best evidence, and this technology has become a part of that.”

At what point, however, does good police work infringe on Americans’ right to privacy in an age when we live our lives tethered to our digital assistants?

“We let these devices into our homes and we’re not really aware of what the implications are,” says Katharina Kopp of the Center for Digital Democracy. “More and more areas of our lives that had once been considered private are now contested spaces.”

Dabate is still awaiting trial, but the case and others like it are raising questions about the nature of privacy in the digital age. Americans are increasingly relying on high-tech gadgets to improve their quality of life. These devices include internet-connected security systems, fitness trackers like the Fitbit, smartphones, and personal assistants like Apple’s Siri or Amazon’s Echo, which is also known as Alexa.

But police are beginning to see these devices as something else entirely. Since they continually collect and store data about us whether or not we realize it, they can be used as evidence gatherers and silent witnesses.

“It is definitely something we are going to see more of in the future,” says police detective Christopher Jones of East Lampeter Township, Pennsylvania. “As people continue to provide more and more personal information through technology, they have to understand we are obligated to find the best evidence, and this technology has become a part of that.”

At what point, however, does good police work infringe on Americans’ right to privacy in an age when we live our lives chained to our digital assistants?

“We let these devices into our homes and we’re not really aware of what the implications are,” says Katharina Kopp of the Center for Digital Democracy. “More and more areas of our lives that had once been considered private are now contested spaces.”    

The right to privacy is based on the Fourth Amendment to the Constitution, which prohibits “unreasonable searches and seizures” (see “The Fourth Amendment,” below). But the courts are still figuring out how to apply that 18th-century phrase to our 21st-century society.

When the Framers wrote the Fourth Amendment in 1789, they had in mind the British soldiers who before the Revolution could enter colonists’ homes to search and seize their belongings without permission. The Framers could never have imagined smartphones, Fitbits, or Alexa.

The most important ruling so far on the issue of privacy and technology was the Supreme Court’s 2014 decision in Riley v. California. The Court ruled that police need to ask permission or get a warrant from a judge to search someone’s cellphone—just as if they were searching inside someone’s home.

Later this year, the justices will hear a case that could determine whether police need warrants to get tracking information from cellphone companies showing their customers’ locations. Currently, police don’t need warrants for this.

Beyond cellphones, there’s a vast amount of data that’s routinely sent over our devices, and it’s become a rich source for investigators. In many cases, police are not currently required to get a warrant to access this information.

A recent murder case in Bentonville, Arkansas, is getting attention because of the role “smart” devices, including Alexa, have played in the investigation. In November 2015, Victor Collins was found dead in a hot tub in the home of his friend James Bates. Police found signs of a struggle and quickly suspected Bates.

When police looked at the data collected by digital devices in the home, they really began to doubt his innocence. An internet-connected utility meter that automatically records water and electricity usage showed that a huge amount of water was used when Bates said he’d been asleep, suggesting that someone had hosed down the crime scene.  

The right to privacy is based on the Fourth Amendment to the Constitution. This amendment prohibits “unreasonable searches and seizures." But the courts are still figuring out how to apply that 18th-century phrase to our 21st-century society.

The Framers wrote the Fourth Amendment in 1789. They were thinking about the British soldiers who before the Revolution could enter colonists’ homes to search and take their belongings without permission. The Framers could never have imagined smartphones, Fitbits, or Alexa.

The most important ruling so far on the issue of privacy and technology was the Supreme Court’s 2014 decision in Riley v. California. The Court ruled that police need to ask permission or get a warrant from a judge to search someone’s cellphone. They considered this the same as searching inside someone’s home.

Later this year, the justices will hear a case that could determine whether police need warrants to get tracking information from cellphone companies showing their customers’ locations. Currently, police don’t need warrants for this.

Beyond cellphones, there’s a vast amount of data that’s routinely sent over our devices. It's become a rich source for investigators. In many cases, police are not currently required to get a warrant to access this information.

A recent murder case in Bentonville, Arkansas, is getting attention because of the role “smart” devices, including Alexa, have played in the investigation. In November 2015, Victor Collins was found dead in a hot tub in the home of his friend James Bates. Police found signs of a struggle and quickly suspected Bates.

When police looked at the data collected by digital devices in the home, they really began to doubt his innocence. An internet-connected utility meter that automatically records water and electricity usage showed that a huge amount of water was used when Bates said he’d been asleep. This suggested that someone had hosed down the crime scene.  

Then police noticed an Amazon Echo on Bates’s kitchen counter, and they wondered what other evidence it might have collected. Echo has seven microphones and is designed to hear users in any direction up to 20 feet away. Did Bates ask Alexa how to clean up blood? When authorities charged Bates with murder, they tried to get Amazon to turn over all the recordings and electronic data captured by the Echo. The company initially refused, saying it wouldn’t release customer data without a court order.

Bates, whose case is ongoing, ended up allowing Amazon to turn the data over, avoiding what would likely have been a court battle between the police and Amazon. But experts expect such a case to wind up in court at some point.

Then police noticed an Amazon Echo on Bates’s kitchen counter. This led them to wonder what other evidence it might have collected. Echo has seven microphones and is designed to hear users in any direction up to 20 feet away. Did Bates ask Alexa how to clean up blood? The authorities charged Bates with murder. They tried to get Amazon to turn over all the recordings and electronic data captured by the Echo. The company initially refused, saying it wouldn’t release customer data without a court order.

Bates's case is ongoing. He ended up allowing Amazon to turn the data over. That avoided what would likely have been a court battle between the police and Amazon. But experts expect such a case to wind up in court at some point.    

In the meantime, privacy advocates are deeply concerned about all the data being collected by these “always on” devices. The Electronic Privacy Information Center (EPIC) recently sent a letter to the Justice Department and the Federal Trade Commission, asking them to investigate whether the devices violate federal laws against warrantless electronic surveillance.  

“Americans do not expect that the devices in their homes will persistently record everything they say,” EPIC’s letter said. “It is unreasonable to expect consumers to monitor their every word in front of their home electronics. It is also genuinely creepy.”

But while the government and the courts figure out what the rules are, experts say it’s up to everyone to be aware that their devices are listening.

“Today,” says Joel Reidenberg of Fordham University’s Center on Law and Information Policy, “it’s more or less naive to expect privacy when communicating on any of these devices.”

In the meantime, privacy advocates are deeply concerned about all the data being collected by these “always on” devices. The Electronic Privacy Information Center (EPIC) recently sent a letter to the Justice Department and the Federal Trade Commission. They asked for an investigation into whether the devices violate federal laws against warrantless electronic surveillance. 

“Americans do not expect that the devices in their homes will persistently record everything they say,” EPIC’s letter said. “It is unreasonable to expect consumers to monitor their every word in front of their home electronics. It is also genuinely creepy.”

The government and the courts are working to figure out what the rules are. But experts say it’s up to everyone to be aware that their devices are listening.

“Today,” says Joel Reidenberg of Fordham University’s Center on Law and Information Policy, “it’s more or less naive to expect privacy when communicating on any of these devices.”    

Additional reporting by Christine Hauser of The New York Times