Need help with hell

[TheMagicBox]

Ok, I need to know how much damage fireball needs to kill CI's in hell. Obviously the more the better but what is the lower end amount of damage i need to kill? How fast will this kill them? This will be used for CI's exclusivly in single player games. Ill let the rest of my party handle them in group games B)

Any help or experiance in this area would be greatly appreciated.

Thanks.