What's More Important?

Which is more important; justice or vengeance?  The balcony collapse in Berkeley, California that killed six students has been at the front of everyone's mind recently.  The fear that gripped so many families as we waited to hear if is was our child/brother/sister/cousin that had been injured or killed is still fresh in our minds.  The heartache we feel for those families who've had to travel to the US to claim the body of their loved one and those that are even now sitting next to bedsides in hospitals over there waiting for the all clear is never far from our thoughts.  And now it's been reported that Berkeley PD aren't going to conduct a criminal investigation into the tragedy.
Emotions are high and someone will be out for blood.  It's a human trait, the need to see some kind of justice for such a loss.  But would it be justice or could this feeling be more simply described as vengeance?  I don't condemn vengeance, I can be a pretty vengeful person myself if someone I love is hurt.  Hearing that there wasn't going to be a criminal investigation didn't actually register with me until my husband commented "Oh dear."  And that got me thinking.
When The New York Times published an article that shone a negative light on the J1 visa programme the internet, radio & news stations all lit up with outraged comments.  The righteous anger was well and truly alive at the callous disregard shown by the publication towards the horrific ordeal many families were (and still are) going through.  Personally I think that the Times were far too quick to bring something like that up mere days after the tragedy.  So now I'm trying to figure out how people might react to the recent news that the Berkeley police are refraining from an active investigation.
With the announcement that emergency legislation is going to be brought in by the city of Berkeley are people going to be satisfied?  I don't think so.  Young lives were lost and families shattered by criminal neglect as far as I'm concerned so I think that some form of justice is required.  Which brings me back to my first question; justice or vengeance?  I hope that justice will win out and some form of recompense will be delivered to those families that are heartbroken and grieving, but the potential for vengeance is there and with emotions so high it's hard to tell the difference between them.
Personally my thoughts and prays are with those families who need them most now and while I breathed a sigh of relief when I heard that my own cousin hadn't been involved I still remember that fear.  Those few moments between when you hear the news and have someone tell you that the person you're thinking of is okay are like a bucket of ice water dumped over you.  May some form of comfort find those families who didn't get that phone call that said "I'm okay" and may a tragedy like this never occur again.