Need some code help, one time use weapon no aggro

[Wasteland Defender]

ScriptName NoAttackScript
begin ScriptEffectStart
  if ( GetCombatTarget == player )
IgnoreCrime 1  
StopCombat 
player.RemoveItem 001healsyringeknife 1 1
endif
End

 

Basically I'm trying to make it so that when you stab an NPC with the knife, they don't attack you

I've been trying to learn a bit of scripting and this is all I can get out of hours of work

 

It simply doesn't want to work and I'm totally lost

 

What I specifically need it to do is

 

Have the npc's disregard your assault and have the item you used to attack them removed.

 

Any help would be appreciated!