They don’t say “He about died at 3pm”
My ex-sister-in-law (RIP) shot herself in the head. When found she had been dead for 12-24-36 hours or so. Time of death was fixed at the discovery of her body. She could have lingered unconscious for days and outward signs of decomposition cannot be used to pinpoint time of death.
No but they can pin it down to a few hours, they do it by body decomposition or lack thereof, when he last swiped his badge, etc.