Exhumation involves legally digging up a buried body and can be done for several reasons: to identify the body, determine the cause of death if foul play is suspected, or recover evidence buried with the body. The exhumation process is supervised by a magistrate and doctor and involves carefully excavating the grave and examining the remains for marks, injuries, or samples that can aid in the investigation. Identification is attempted even if the body has decomposed, and samples are collected and preserved as necessary for analysis to determine factors like poisoning or the cause of death.