Seeing things like these makes me instantly want to reconsider my stance on capital punishment. Passion and instinct demand these terrible examples of mankind to suffer the ultimate punishment for their crimes, however, if death is a excusable punishment for this abhorrent crime.... Then the state would be tainted as a murderer.
So, I'm going to advocate savage abuse and beatings on them instead.
But in all seriousness, there's something severely wrong with all individuals involved. This case needs extreme scrutiny to determine what happened. If the youngest of the criminals where coerced or forced to participate (as difficult this is for me to say as I believe that everyone above the age of 10 has some kind of ethical compass, this needs to be said), this could be considered a circumstance that needs to be considered in their judgement.
An example needs to be set. But we cannot set a example that entails bloody retribution and medieval justice, as it would only broadcast to the world how violent and de-humanizing the legal system can become when emotions are involved. Even at the shadow of this despicable violation, a fair trail is mandatory. As much as it makes me frown with disgust to imagine the torment of the 7 year old girl, the bastards have rights even when they don't deserve them.