They are seeking 'retribution for' the killings.
The killer acted without fear of 'retribution'.
(..) Now while it's not wise to assume, in this instance, I think it's pretty safe. Point being… don't get so carried away with your retribution. You lose sight of why we're here. – You think I lost sight, of that? – Yes, I do! Stop antagonizing Candie! You're going to blow this whole charade, (..)2012 Django Unchained