Why is a forensic autopsy necessary if the cause of death seems obvious, such as a gunshot wound?

A complete autopsy examination can help determine details necessary for determining the manner of death and provide information that may need to be presented in court. For example, details in an autopsy report may include determination of direction of the wound, extent of injury, number of wounds, and range of fire (distance from muzzle to victim). Specimens are acquired during the autopsy and retained for testing of drugs and alcohol, or other diagnostic medical testing. The autopsy will exclude alternative causes of death.