Wouldn't Perper only be able to speculate on what people told him unless someone did a liver temperature ASAP at the hospital?
Did Anna have a temperature when she laid down. The body cools at a pretty particular rate. Regardless, the time span between alive and dead is vey small and it seems witnesses would be the highest evidence in determining the time of death.
Well, I had thought an autopsy could determine time of death - but that may not be right. If not, then, yes he is purely speculating on time of death. There has not been a death certificate issued yet for Anna's death has there? Wouldn't time of death be on the death certificate? Put there by the ME?