npc_destroy
npc_destroy is a console command available in all 
Source games.
The npc_destroy console command is a debugging tool that destroys NPCs. Destroyed NPCs are silently removed, so outputs such as "OnDamaged" and "OnDeath" are not fired, nor are ragdolls created. Destroyed NPCs carrying weapons will drop the weapon before removing themselves.
This command flags the NPC with a note to destroy itself, so if AI is not running (due to the ai_disable command), the command will be ignored.
Note:The game must be in Developer mode for this command to work properly.Usage
Note:The targetname/classname parameter supports wildcard but anything after the wildcard is ignored. For example, npc_destroy npc*zombie will destroy any NPC whose targetname/classname starts with npc no matter what text follows after wildcard.npc_destroy- This will destroy the NPC under your crosshair, if any.
npc_destroy <entity index>- This will destroy the NPC matching the specified entity index, if any.
npc_destroy <name>- This will destroy all NPCs whose classname or targetname matches the specified name.
npc_destroy *- This will destroy all NPCs in the map
