Heir s Right in the Murder from the Islamic Law Viewpoints (Concepts Analysis Part)

God in the Holly Quran has called murder as an atrocity on human life (Maede 5:32) and there is an authority for the Heir (Asra 17:33). This study entitles" Heir 's right in the Murder". In order to have a clear idea related to this issue the writer has done a research in the Islamic rights sources. Although the topic of this research is general, but the study is limited to retaliation and blood-money. Due to this fact that the retaliation is undeniable in Islam, all the considerations of this research are centered to find an answer for one main question: how is retaliation substituted by blood – money?There are some theories to answer this question as follows:1-There is no other right for the heir except of retaliation.2- Retaliation and blood-money are optional.The researcher believes that justification of these two theories are not convincing, Due to the shortcomings of the two theories mentioned above, the researcher has designed a new theory called The theory of replacement of retaliation by blood-money when retaliation is impossible. This part of the research involves the general aspects, analysis and the definitions of the key concepts.