:salamext:
Without getting into too much detail, for major sins hudood (prescribed punishment) is to be implemented. Such a case is to be taken to an Islamic court and the Muslim judge is the one who will rule on this case. There are a number of things to be taken into account by the judge that will determine the outcome of the murderer i.e. why he killed, who he killed (i.e. was he a Muslim or not), whether he has to pay the blood money or should will he be killed for his crime (hadeeth of the Prophet (:saws:) - a tooth for a tooth, an eye for an eye and a life for a life) etc. This is up to the Muslim judge and this is practiced in Muslim lands. Therefore since no body seems to know what they are talking about I would advise all participants of this thread to follow the example of insane insaan who quoted a passage from islamqa instead of throwing personal opinions.
If the first article was too short then this may help.
http://www.islamqa.com/en/ref/10923
Lastly because everyone just wants to have some sort of a say without really knowing the ahkaam (rulings) or even basic knowledge on this subject this thread is officially closed.
To the thread starter, you may PM me if you wish to discuss this.
:threadclo