My condolences to the families of the victims-- their cries for vengeance are understandable and, I say, justified. As for the perpetrators, they should be punished in the most painful and protracted way possible.
That said, let me discuss human rights, which I'm sure the perpetrators will seek refuge in if they are caught and found guilty. Of course the accused, who are presumed innocent, should be accorded due process and all the protection under the law. But what do we do with those who are guilty of the most violent and heinous of crimes? What basis is there to say that the death penalty should be off the table? Generally, what rights of criminals, who despite their actions remain biologically human, may or may not be withdrawn?
Human rights are the set of rights and freedoms that everyone is endowed with by virtue of being born human. No one is born without human rights, and no action is required to acquire these rights. Everyone is entitled to the protection of their human rights, and no one may deny others these rights. However, one can do actions (i.e., criminal activity) that result in the State's (as the representative of society) legitimate and just withdrawal of some of these rights. For example, Article 13 of the Universal Declaration of Human Rights (UDHR) declares that "everyone has the right to freedom of movement". But incarceration-- a withdrawal of this right-- is a universally accepted penalty for criminal activity. So if Article 13 of the UDHR can be withdrawn as a consequence of certain crimes, why not, say, Article 3 (right to life) or Article 5 (protection from torture or cruel punishment)?
One argument is that some human rights are inalienable (e.g., right to life) and others are not (e.g., right to free movement). Alston (2005), who famously visited our country last year, puts it softer as the prioritisation of human rights, that some rights are more important than others and should thus be pursued more rigourously. Accepting that such a dichotomy of human rights exists, how do we detrmine which ones are inalienable (or more important) and thus cannot be withdrawn as a consequence of criminal activity?
Answers based on the Divine, religion, or some "self-evident" truths are flimsy because they cease to persuade once the underlying assertions and dogmas are disputed-- they are only persuasive for the converted. Natural law, social contract, Kantian morality, and evolutionary game theoretic arguments provide sound bases for the universal existence and protection of human rights, but give no objective limits on the punishment for those who violate them.
The strongest argument against the withdrawal of some human rights is the imperfection of the judicial system-- errors can occur and the innocent may be convicted. In this case, certain rights should not be withdrawn if there is a nonzero probability that the convict is actually innocent, especially if the withdrawal of such rights cannot be reversed. Indeed, it is better to err on the side of protecting human rights than withdrawing them. [I use a similar line of argument in my stand on abortion.] However, this is a practical argument that has no bearing on the merits of what punishments should or should not be allowed. After all, this argument falters if there is absolute certainty that the convicted criminal is guilty (say, there is untampered video of him shooting the victims).
The way I see it, the set of human rights that can be withdrawn as a consequence of criminal activity is a matter of social choice. There is no objective reason why some punishments should be allowed and others should be prohibited-- it all depends on the preferences of society. Thus, if society decides that violent criminals like the Laguna robbers should receive capital punishment (i.e., their right to life should be withdrawn), there is no objective reason to say that this should not be done; the only real constraint is society's sensibilities and public opinion.
Violent crimes like the Laguna robberies strain the rationale behind the limits on their punishment. If we subscribe to the social contract theory of human rights, a criminal should be deemed to have surrendered all his human rights if he decides to use violence on his victim. Perpetrators of heinous and violent crimes, if we are absolutely certain of their guilt, should be punished harshly, severely, and mercilessly.
If you disagree with me, do leave a reply and set me right.