Livor mortis or postmortem lividity or hypostasis is the setting of
blood in the lower portion of the body, causing a purplish red
discoloration of the skin, when the heart is no longer agitating the
blood, heavy red blood cells sink through the serum by action of
gravity. This discoloration does not occur in the areas of the body that
are in contact with the ground or another object, as the capillaries
are compressed. Coroners can use the presence or absence of livor mortis
as a means of determining an approximate time of death. It can also be
used by forensic investigators to determine whether or not a body has
been moved. Livor mortis starts 20 minutes to 3 hours after death and is congealed
in the capillaries in 4 to 5 hours. Maximum lividity occurs within 6-12
hours.