The Anthony Aiello case was a 2018 San Jose homicide prosecution in which a 90-year-old man was charged with murdering his 67-year-old stepdaughter, Karen Navarra, after data from her Fitbit fitness tracker placed the moment her heart stopped inside a window when only Aiello was with her. Aiello maintained his innocence, his health collapsed during a year of pretrial detention, and he died in custody in September 2019 before the case reached trial. Prosecutors then dismissed the charges.1Santa Clara County District Attorney’s Office statement following Aiello’s death.
Who Karen Navarra Was and How She Was Found
Navarra was a pharmacy technician who had worked at the Regional Medical Center of San Jose for roughly 45 years. She lived alone in the Berryessa neighborhood of North San Jose. On September 13, 2018, a coworker went to check on her after she failed to show up for work, entered through an unlocked front door, and found her dead at her dining room table.
Navarra had a deep laceration on her neck, wounds on the top of her head, and a large kitchen knife placed in her right hand. Chairs were toppled and drawers pulled open. An autopsy the next day classified the death as a homicide, finding multiple skull fractures and wounds likely caused by an object with a sharpened edge such as a small hatchet or axe. Several wounds would have been immediately incapacitating, and the medical examiner concluded they were not self-inflicted. Investigators determined the scene had been staged to look like a suicide.
How the Fitbit Pinpointed the Time of Death
Navarra wore a Fitbit Alta HR on her left wrist. The device continuously tracked her heart rate and movement, syncing to her desktop computer every 15 minutes, which then uploaded the data to Fitbit’s servers. Detectives obtained a search warrant on September 19, and a Fitbit director extracted the records.
On September 8, 2018, Navarra’s heart rate spiked sharply at 3:20 p.m., then slowed rapidly. By 3:28 p.m., the device stopped registering any heart rate. No steps, movement, or heart activity were recorded after that moment. That fixed the attack and her death to an eight-minute window on September 8, five days before her body was discovered.
A Ring camera at a nearby home showed a gray 2007 Toyota Corolla, registered to Navarra’s mother and driven by Aiello, parked in Navarra’s driveway from 3:12 p.m. until at least 3:33 p.m. that day. Because both the Fitbit and the surveillance camera used internet-synchronized clocks, their timestamps aligned. Navarra’s heart stopped at 3:28 p.m. while Aiello’s car was still in her driveway.
What Aiello Told Police, and What the Evidence Showed
Aiello was Navarra’s stepfather, married to her 92-year-old mother. When detectives interviewed him on September 14, he said he had visited Navarra on September 8 to deliver pizza, arrived around 3:00 p.m., stayed only five to seven minutes, and left her alive. He also said that after returning home he saw Navarra drive past his house with an unknown passenger.
The surveillance footage put his car at her home for more than 20 minutes, not five to seven. Investigators pulled footage from the area around Aiello’s own residence and found no sign that Navarra’s car ever drove by that day.
The Physical Evidence From Aiello’s Home
On September 25, a judge issued a Ramey warrant for Aiello’s arrest and a search warrant for his residence. During the search, investigators recovered a pair of men’s pants with blood on the knees, a white tank top with blood splatter, and a gray button-down shirt with splatter patterns. Presumptive tests on sinks in the master bedroom and a converted garage area came back positive for blood, which investigators read as evidence of cleanup.
In a custodial interview, Aiello denied the killing. Confronted with the Fitbit and surveillance timeline, he suggested someone else must have been inside Navarra’s home. He said the blood on his clothes came from cutting himself, but investigators told him the stain patterns were consistent with splatter, not a small cut. Left alone in the interview room, he was recorded saying, “I’m done.”
Police never publicly identified a motive. Detectives asked about financial and personal motives, and Aiello denied both. Cash, jewelry, electronics, and financial documents were left untouched at Navarra’s home, which supported the view that the ransacked drawers were part of the staging rather than a robbery.
Charges, Bail Fight, and Failing Health
Aiello was charged with murder under California Penal Code Section 187 with an enhancement for personal use of a deadly weapon. He was held without bail at the Santa Clara County Main Jail and pleaded not guilty. A criminal grand jury indicted him on August 7, 2019.
His health deteriorated sharply during roughly a year in custody. His daughter Annette and his attorney, Edward Caden, described worsening congestive heart failure, diabetes, and kidney problems. He became incontinent and wheelchair-dependent, and according to the defense was transferred between the jail infirmary and Valley Medical Center at least a dozen times. At an April 2019 court appearance, he arrived in a wheelchair, shackled, using an assisted hearing device.
Caden asked for bail on health grounds, arguing the jail could not properly care for him. Prosecutors opposed release, calling him a flight risk, pointing to a killing they said was staged to look like a suicide as proof of his capacity for deception, and citing what they described as “copious DNA and blood evidence.” The court denied bail. In August 2019, Annette Aiello and supporters from the community advocacy group Silicon Valley De-Bug rallied outside the Santa Clara County Hall of Justice. “He doesn’t belong here, he didn’t do anything,” she told reporters. The Santa Clara County Sheriff’s Office said Aiello received round-the-clock medical care and that “the age of this inmate has not been a notable concern.”
The Defense’s Challenge to the Fitbit Evidence
Caden argued publicly that a 90-year-old man could not physically have carried out the attack. “This is so over-the-edge unusual for someone to be charged at age 90 with first-degree murder,” he said. “There’s no way he could have carried out the offense that has been charged.”
He attacked the Fitbit evidence directly, calling it “the most razor-thin evidence I’ve seen” and “a gross overreach,” and stressing that a Fitbit “is not a medical device.” He also pointed to a cigarette butt recovered from the scene that carried DNA matching neither Aiello nor Navarra, arguing it supported the theory that a third person had been in the home. The defense suggested the blood on Aiello’s clothing came from a superficial wound Navarra already had when she hugged him during his visit.
Death in Custody and Dismissal
Aiello died on September 10, 2019, at a San Jose hospital at age 91, from complications of his pre-existing conditions. Prosecutors moved to dismiss the murder charge, the standard step when a defendant dies before a case concludes. Chief Trial Deputy Angela Bernhard of the Santa Clara County District Attorney’s Office said, “The case is over.”
His family rejected that as closure. “My father’s death doesn’t end the suffering,” Annette Aiello said, “and his prophecy that they were waiting for him to die so he would be denied his day in court has been proven true. My father was killed by pretrial incarceration.” Caden maintained his client’s innocence and said investigators had not pursued other leads.
What the Case Meant for Wearable Data in Court
Because Aiello died before trial, no court ever ruled on the admissibility of the Fitbit evidence against him. The case is still cited as one of the earliest high-profile homicide investigations to lean heavily on data from a consumer fitness tracker.
Later cases have gone further. In Connecticut, Richard Dabate’s account of a home invasion was contradicted by his wife’s Fitbit, which showed her moving for about an hour after he said she had been shot. He was convicted in 2022 and sentenced to 65 years, and in March 2025 the Connecticut Supreme Court unanimously upheld both the conviction and the admissibility of the Fitbit data. Defense challenges to wearable evidence, typically aimed at proprietary algorithms and sensor accuracy, have so far mostly failed at the appellate level, with courts treating those questions as matters of weight for the jury rather than bars to admission.