Not all kidnappers are THIS bad.
These pieces of $hit killed their victims even if they got the money, they were MURDERERS. There are some parts of the world like Mexico and Somalia where kidnapping has become an "industry" and as long as the loved one of the victim pays the demanded money without any funny business they REALLY DO LET THE VICTIM GO.
How effing evil do you have to be to kill the victim anyway? Jesus Christ.