Transformation of Retaliation to Compensation In Case of Death of the Murderer or Lack of Access to His

The primary right of blood heirs in the murder is retaliation. but if there was permanent or temporary obstacles in implementation of this right there is disagreement between scholars about nature of their second right. some believe that religious reason require we can not determine compensation. but some believe that once there was obstacle in implementation of retaliation blood heirs can demand compensation. some scholars have an intermediate view that require neither full drop nor full confirmation of compensation. they say that criterion is fault murderer or lack of it in process of implementation of the punishment. Intellectual and religious foundation of this approaches show that the first approach is invalid.and we should accept consolidation of second and third approach.