Fitbit data may have helped catch one of its customer’s killers, and not for the first time.

According to numerous media reports, a 90-year-old visited his stepdaughter at her home in San Jose, Ca. earlier this month, where he says he brought her pizza and visited briefly. But according to data provided to authorities by Fitbit, data from the stepdaughter’s Fitbit Alta wristband device — which tracks one’s heart rate and the number of steps taken during the day — showed a “significant spike” in her heart rate during the man’s visit, followed by a “rapid slowing.” Eight minutes after her heart had risen so rapidly, and five minutes after her stepfather left her home, it stopped.