After examining a Fitbit Alta device that Karen Navarra was wearing at the time of her death, police investigators discovered that her heart rate dramatically increased before slowing decreasing and stopping all together – all during a visit with her stepfather, Anthony Aiello.

Police investigators in San Jose, California, have recently used a woman’s Fitbit data to charge her 90-year-old stepfather with murder.

A co-worker found the lacerated body of Karen Navarra, 67, in her bloodied San Jose home on 13 September 2018, according to a report by The New York Times. Five days earlier, her stepfather, Anthony Aiello, 90, had allegedly delivered food to her house – a meeting that ended with Navarra walking Aiello to the door and handing him roses, Aiello told investigators with the San Jose Police Department.

However, investigators examined a Fitbit Alta device that Navarra was wearing at the time of her death and made a discovery that led to the arrest of Aiello. The device was set to automatically sync to Navarra’s home computer, giving investigators access to its data sets. They found that Navarra’s heart rate dramatically increased shortly after 3:20 p.m. on 08 September, before slowing decreasing and stopping all together at 3:28 p.m.

These time stamps correspond to the same time as Aiello’s final visit with Navarra, according to the Times.

Aiello has since been charged with murder and appeared in San Jose court on 18 October 2018.

“From doorbell security footage to Fitbit, technology engineered to solve some of life’s issues are solving serious crimes,” Jeff Rosen, the district attorney for Santa Clara County, told the Times. “We are continually inspired by law enforcement investigators who are thinking outside of the box.”

Fitbit declined to comment on Navarra’s case, but the company’s privacy policy says that it is compliant with legal procedures such as search warrants and court orders.

In 2017, police investigators in Ellington, Connecticut, similarly used a woman’s Fitbit data to charge her husband in her December 2015 murder.