Valarian's Assassins Mission?Follow

I'm doing the Jabba's palace missions, but I'm stuck on a part where I'm supposed to kill the four "Valarian's assassins." For some reason I keep getting defeated. I'm a level 20, and the NPCs are level 18. I've noticed that the three I can't kill have this claw symbol wrapped around the NPC level indicator. The one I had no trouble killing did not have that symbol.

Is there any trick to this? Does anyone know what that symbol means?

They are "Elite" mobs they probably also have < > in silver or gold at each end of their health bar depending on what level they are.

In order to carry on you are either going to need a small group 2-4 people or a few more levels on them.