How can pools of blood aid in reconstructing a crime scene?

The presence or absence of blood can give valuable information about the nature of a crime. A crime scene with minimal blood but massive wounds to a victim can tell investigators that the site was a possible body dump and not the true scene of the murder.

A crime scene with blood but no victim can also give information. A person cannot survive if too much blood is lost so investigators can tell that the missing individual has been killed because of the amount of blood present.