Livor mortis

Livor mortis. If the body exhibits red, purple, or blue skin discoloration, the person has been dead less than a half-hour. 

The processes of livor, rigor, and algor mortis can be useful indicators of a recently deceased person, but the processes may have expired by the time a body is placed in a shallow or deep grave site. Once these changes have passed, soft-tissue decomposition proceeds through the processes of autolysis and putrefaction (Fiedler and Craw 2003). In a burial environment, it is these processes that are likely to result in the disintegration of soft tissue and skeletonization. 

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