Heart rate data from a Fitbit has been used to charge a man with the murder of his stepdaughter, reports The New York Times. Anthony Aiello had initially claimed that he had left his stepdaughter Karen Navarra’s home within 15 minutes of arriving. However, data from her Fitbit was later compared against security camera footage to prove that her murder occurred while Aiello was still at the property.

The data the Fitbit provided to detectives (in response to a search warrant) showed Navarra’s heart rate spiked at 3:20PM before rapidly declining and stopping completely at 3:28PM. Detectives later discovered bloodstained clothes at Aiello’s property, and he was arrested on September 25th.

The side effects of biometric data

Data from wearables and smart home devices is proving to be increasingly important to investigators as they attempt to solve crimes that lack reliable witnesses. The NYT cites a 2017 Connecticut trial in which Fitbit data was used to charge a man with the murder of his wife. Investigators also requested data from an Amazon Echo in 2017 in connection with a murder that the speaker’s microphones may have overheard.

In Fitbit’s case, it handed over the data from its user’s fitness tracker without issue. The company’s privacy policy explicitly says that it uses the data it collects “to promote the safety and security of ... our users, and other parties.” It says that it “may use the information to ... respond to a legal request.”

Although Amazon agreed to provide subscriber and account information for the Echo device in the murder case, it initially refused to provide the communication data, arguing that voice interactions with Alexa were protected by the First Amendment. The company would later hand over the data at the request of the Echo’s owner, the case’s defendant, after which the charge was dismissed by a judge.

Fitbit’s data has already proven to be a valuable tool for bringing criminals to justice. And as we allow devices to have more and more access to our lives, biometric data cases like this are only going to increase.