Spawning zombie when other zombie is killed

What I wan’t to do is spawn a zombie when the other one is killed

I know how to spawn the zombie when the other one is killed I wan’t to spawn it after the other one is killed and wait 5 seconds then spawn and repeat

for example

var ZombieToSpawn : GameObject;
var ZombieToWatch : Gameobject; ///The zombie that will get killed
var SpawnTime : float; ///// the problem i have is spawning after a specific time

function Update(){
if(ZombieToWatch == null){
//spawn the zombie after 5 seconds or so at the transform of this object
}

}

Read the docs?