Apologies for writing in english.
Firstly, we should examine what are the purposes for "punishment" metered out by society after a conviction for a crime:
1. Punishment - while obvious it needs to be said. Anti-social actions are punished.
2. Example - both for the offender, but also as an example of "cause-and-effect" to society as a whole. This is in the hope that it will deter others from committing a crime, and hopefully the offender themselves.
3. Revenge - The victims, and society, feel the need for an action of revenge.
4. Re-habilitation - The hope that by helping a "criminal" understand the implications of their actions upon the victims, and society, that the "criminal" will choose to act differently in the future.
In no particular order....
If we look at the case in England and compare it to the case on Kungsholmen, we see many similarities. The age of the perpetrators is similar: that at least one of the perpetrators is known as a "violent" to the authorities: that the acts were perpetrated under the influence of alcohol: and that the fight/death culminated from a verbal exchange.
Then we need to consider the act itself. A verbal exchange escalates to a frenzied attack by a group toward an individual. If the intent was not to kill, there certainly was no attempt by the perpetrators to preserve the life - or even consider the life - of the victim.
I feel the English court to be correct in convicting for murder in this case. At 16 most people are aware that kicking someone in the head is likely to kill them.... Therefore making a decision to do that is an attempt to kill.
Some have commented that 12 years is a harsh sentence for a 16 year old. Maybe! But if society hasn't succeeded in 16 years, how much hope have the psychiatrists in 12?
I'm not sure that sentences in this case are "just". But, I lean toward the idea that the sentences in the Kungsholmen case are comical- if you look back to my first four assumptions.
I sure as shit don't have the answers here, but it needs to be discussed.