Sorta. Well technically yes. Though it's easier for undetermined. His mother has been missing for over 5 years. she can be legally be dead. And normally cases go cold in less than a month.
Yes, if the amount of blood found is enough to rule out a person's death and the officer said exactly that. A person can't survive after 40% percent of their blood volume, so you find a crime scene with 2 litres of blood or more means the victim is dead. What will determine if it's a homicide or not is the evidence.
So informative , thank you guys(⌒▽⌒)
Is it truly possible to close a case as a homicide without finding the corpse or murderer ?