Anyone convicted of murder can have a page unless there is real evidence of a corrupt trial such as Chinese political figures. Exact definitions of murder vary a little from place to place but generally this involves a person who wanted to seriously hurt somebody and did so, killing them.
Some places like parts of America also have a form of murder where somebody acts so extraordinarily recklessly that it is felt better to charge murder than manslaughter. This wiki is neutral so we have no opinion on which way of prosecuting is better, but these cases count for this site because any case that bad would still count as a very heinous manslaughter.
Exceptions: In some places like England it is still murder to kill somebody as an act of mercy even where the person killed was in great and terrible pain and begged to die. Consider these very carefully. Although wrong it's often the case these were done for honourable reasons such as helping a loved one's wishes and preventing suffering. These cases are not automatically exempt! But in most cases it would be unfair to label these as heinous criminals.