How to check for an entity dying

Im trying to make a plugin for fun where if a Special Zombie named "Life" died the game would kill the player. But there isnt any way i know of to check for a mob dying. How would i do that?

 

Pre-Death:

PHP:

public function onDamage(EntityDamageEvent $event){
    if(($zombie = $event->getEntity()) instanceof Zombie && $zombie->getNamedTag() === "Life" && $event->getDamage() >= $zombie->getHealth()){
        //Pre death.
    }
}


Post-death:

PHP:

public function onDeath(EntityDeathEvent $event){
    if(($zombie = $event->getEntity()) instanceof Zombie && $zombie->getNamedTag() === "Life"){
        //Post death.
    }
}


 

Heard a lot about those, but does that actually make any difference?

 

No, we put them there for fun

Spoiler

sarcasam