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Rigor mortis, the postmortem stiffening of muscles due to chemical changes in muscle tissue, typically lasts about 2 to 3 days before it begins to dissipate. This process is influenced by various factors such as temperature, physical condition of the deceased, and the circumstances surrounding death.

Initially, rigor mortis sets in within 2 to 6 hours after death, reaching its peak stiffness at roughly 12 hours. Following this peak, the rigor gradually fades away as the muscle tissues begin to break down. By about 48 to 72 hours postmortem, rigor mortis effectively disappears as decomposition processes continue. Understanding the timeframe of rigor mortis is crucial for forensic analysts as it can provide insights into the time of death, which is a vital piece of information in crime scene investigations.