1.2.2 Time of Death

Rigor Mortis

After death, the muscles contract and stiffen. Typically begins 2-4 hours after death. First observed in head and neck and then arms and legs. Full rigor happens after 8-12 hours. After about 36-48 hours, rigor fades and decomposition begins.

Decomposition

Begins 36-48 hours after death. Body turns greenish and may swell or bloat as bacteria break down tissue and release gas. Includes nasty smell.

Adult Fly

After 145 hours, adult fly emerges and can fly within a few hours to continue the life cycle by mating and laying eggs.

Larvae-Third Instar

After 47-51 hours, the second larvae shed and the third emerge. They continue to remain a maggot mass.

Glaister Equation

Used to approximate time since death. Measured in F.

Larvae-First Instar

Within 12-24 hours o being laid, eggs hatch and larvae emerge. Larvae remain together as a maggot mass and won't move individually until the reach the pupa phase.

Blue Bottle-Fly Egg Cases

Within hours of death, flies appear on corpse and lay eggs. They lay around 200-300 eggs.

Pupae

After about 132 hours, the larvae do their final molt. The exoskeleton hardness and gets darker. Migrate away from corpse individually to complete their transformation to adult flies, by burrowing into the ground.

Celsius to Fahrenheit

(C x 1.8) + 32 = F

Liver Mortis

Blood settles on body parts facing the ground due to gravity. This is the bluish color seen on the skin where the blood pools. Early signs of this occur within 2 hours. Full signs occur with 5 hours and lividity is fixed in place after 8-12 hours.

Scene Markers

Clues left at the scene (texts, emails, mail, dirty dishes, or broken clock) that establish a timeline.

Larvae-Second Instar

In 24-48 hours, the first instar larvae shed their exoskeletons, becoming second stage larvae. They continue to remain as a maggot mass.

Algor Mortis

Postmortem change in body temp Body temo usually reaches the temp of the surrounding environment within 24 hours. Body temp changes 1.5 degrees per hour (estimated). Room/air temp, exposure to sun/win/snow or clothes on body impact this estimate.

Body Farms

Research compound where scientists study what happens to human bodies after death. First founded by Dr. William Bass in 1972 at the University of Tennessee in Knoxville. Bodies are left outside to decay in heat/cold/humidity and observed to understand factors in postmortem changes.

Forensic Entomologists

Scientists who study arachnids, such as mites, spiders, ticks and insects such as flies, as they pertain to criminal investigations.

Clouding of Corneas

The clear part of the eyes become milky or cloudy within the first several hours of death.

Insect Activity

The presence of eggs, larva, or full grown bugs provide a timestamp for how long the body has been decaying.

Legal Time of Death

The time of death recorded on the death certificate; based on when the body was found or physically pronounced dead.

Estimated Time of Death

The time the medical examiner estimates that the death occurred.

Physiological Time of Death

The time when the descendant's vial functions actually ceased.