SAN JOSE (CBS SF/AP) — A San Jose woman’s Fitbit helped provide clues to police investigating her death, leading to the arrest of her 90-year-old stepfather this week.

San Jose police said Tony Aiello was arrested Tuesday on suspicion of murdering 67-year-old Karen Navarra on Sept. 13.

READ MORE: UPDATE: Flood Waters Shut Down Lanes Of I-880; Alameda's Harbor Bay Parkway, Silverado Trail In Napa

Officers responding to a welfare check for Navarra on the 1000 block of Terra Noble Way found her with visible injuries and unresponsive, police said. She was pronounced dead at the scene.

The San Francisco Chronicle reported Friday that Navarra’s Fitbit recorded a rapid rise in her heart rate before a sudden drop-off to nothing, helping investigators piece together clues to her death.

The newspaper reported that an autopsy found “multiple deep and intrusive wounds” to her head and facial area, likely inflicted by a small hatchet or ax.

READ MORE: Atmospheric River: Santa Cruz County Officials Lift Evacuation Orders For CZU Fire Burn Zone

Police said nearby cameras captured Aiello’s car at Navarra’s home on Sept. 8 at the same time her Fitbit showed her heartbeat rapidly falling.

Aiello was booked into the county jail without bail on suspicion of murder.

It could not immediately be determined if Aiello has an attorney.


MORE NEWS: Atmospheric River: San Francisco Bay Area Takes Wild One Day Ride From Extreme Drought To Flooded Streets

© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press and Bay City News Service contributed to this report.