A 91-year-old California murder defendant who was arrested last year after his stepdaughter's Fitbit allegedly provided clues in her death, died in a hospital Tuesday.

Anthony Aiello died at the Santa Clara Valley Medical Center Hospital in San Jose where he had been taken Aug. 22 due to “deteriorating health” from a pre-existing condition, authorities said, according to The San Francisco Chronicle.

Aiello was awaiting trial in the Sept. 8, 2018, death of Karen Navarra. The 67-year-old's body was discovered in her home after she failed to show up to her pharmacy technician job.

Aiello's arrest made headlines after authorities found Navarra's wristband Fitbit device, which tracked her steps and heart rate.

Her death was initially thought to be a suicide but an autopsy revealed she died of blunt force trauma.

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Aiello was married to Navarra's mother and said he visited his stepdaughter on Sept. 8 to bring her a pizza. He said he saw her drive by his home hours later with someone.

However, investigators said Navarra's Fitbit recorded a rapid rise in her heart rate before it dropped off the day she died. Cameras captured Aiello's car at her home at the time the fitness device recorded the rapid heartbeat plummeting.