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.