A Brutal Murder, a Wearable Witness, and an Unlikely Suspect

With smartwatch heart trackers, “if you’re trying to determine if someone’s heart rate is exactly 80 beats versus 90 beats per minute, that’s a really hard thing,” says kinesiology professor Lisa Cadmus-Bertram. “If you’re trying to determine if a heartbeat has ended, in my experience with these devices, they should be able to do that quite easily.”