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Forensic Science | 8.2 Human Remains Lab Background and Purpose: You are employed as a medical examiner in a large metropolitan city. You are called to crime scenes with deceased victims on a regular basis. One of the main objectives is for you to approximate the time of death if it is unknown. In this lab, you will demonstrate your skills using livor mortis, algor mortis, and rigor mortis to estimate the time of death. You will also demonstrate your proficiency in identifying visible marks on the body, which you may want to review from lesson 8.1. You will also be asked to decide if a body has been moved from the original position. Materials: ● Pen ● Paper ● Calculator Procedure: You will be presented with 3 tasks in this lab: 1. Identify the time of death of 4 individuals using 3 methods. 2. Identify if the 4 bodies have been moved from their original position. 3. Identify and document data about any visible marks on the bodies. All data gathered from the case scenarios below will be placed in the data table labeled “ Data Table 1 ” and will help you to accurately complete “ Data Table 2 ” and make sound judgements on the analysis and conclusion sections that follow. Some things to keep in mind while completing this lab: ● The Glaister equation for estimating time (in hours) since death is: (98.4°- rectal temperature) 1.5 ● Livor mortis can be used to give a rough estimate of time since death. If the areas of livor mortis turn pale when pressed, the person has been dead less than 12 hours. If the areas of livor mortis remain dark, the person has been dead longer than 12 hours. ● For this lab, assume that rigor mortis begins 2 hours after death and ends by 48 hours after death. Rigor mortis varies by temperature and environment, but the above estimates are the average and are to be used for determinations in this lab. © Copyright Michigan Virtual 2020 Revised 4/22/2020 Page 1

● Livor mortis can be used to determine if a body has been moved after death. Recall that livor mortis is caused by blood settling in the lowest points on the body. For example, if a body is found lying face up on a flat surface, it would be expected that the livor mortis patterns would be on the back. ● Review the types of visible wounds discussed in the content before completing this lab. Recall that incised wounds can be either slashes or stabs. Slashes are wide, but not deep and stabs are deep, but not wide. ● Recall that lacerations can be distinguished from incised wounds by the presence of “tissue bridges”, abrasions and bruises next to the wound. ● Recall that bruises follow a somewhat predictable coloration pattern that can help us to estimate the age of the bruise. Use the following chart to date bruises in this lab: Bruise color Age of bruise Purple/red 1-18 hours Brown ~1-2 days Green ~2-3 days Yellow ~3-7 days Read each case story carefully and look for clues that can help you in your estimations and decisions. Once you have read each case story, complete the sections indicated in Data Table 1 and Data Table 2. After you have completed all 5 case stories, look over your data and answer the analysis questions. You may wish to review your content before beginning this lab so that you are familiar with the decomposition process in the human body. Case 1 (EXAMPLE) A body is found in an abandoned building lying face down. Upon arrival, the body temperature was measured to be 76.2°F. Livor mortis was found all along the back with a pale area in the small of the back. When pressed, the areas of livor mortis remained dark. Visible marks were found as follows: one incised wound on the lower right side of the abdomen that was measured to be 1 inch deep and 6 inches wide, one bruise that was purple on the upper left arm. The body was found to have rigor mortis throughout the entire body from head to foot. Case 2 The body of an older man was found in the nearby state park. The temperature outside was 41°F at the time the body was found. The body temperature was found to be 42.7°F. The body was lying face up with livor mortis patterns along the length of the back except in the area of the small of the back. When pressed, the areas of livor mortis remained dark. No visible marks were found on the body. Rigor mortis was present throughout the body. © Copyright Michigan Virtual 2020 Revised 4/22/2020 Page 2

Case 3 A body is found slumped in a sitting position with face leaning downward on a bus station bench. It appears the person was sitting on the bench waiting for the next bus. The body temperature was found to be 93.2°F. The person had livor mortis patterns on the face in the nose and mouth area, in the lower legs and feet, and on the buttocks and back of the thighs. When pressed, the livor mortis patterns turned pale. A green bruise was found on the upper left shin. No other visible marks were found. Rigor mortis was found to be present in the face and head. Case 4 A body is found lying on its left side in a basement. The body temperature is recorded as 83.4°F. Rigor mortis is found to be present from the head to the knees. Livor mortis was found present along the right side of the body and turned pale when pressed. Purple bruising was found on the left and right side of the neck with small dark purple spots on the skin in the area. Data Table 1 (5 points) Case # Body Temp. (°F) Glaister equation estimation of time since death (in hours) Livor Mortis (describe) Rigor Mortis (describe) Visible Marks (describe) 1 example 76.2 98.4 - 76.2 = 14.8 hours 1.5 Areas of livor mortis remain dark when pressed (all along the victim's back), with one small pale area Exists throughout the entire body (Head to toe) Incised wound on lower right side of abdomen (1 inch deep, six inches wide) A purple bruise on the upper left arm 2 42.7 98.4-42.7/1.5= 37 Hours There were livor mortis patterns along the back, except in the area of the small of the back. When pressed, the areas of livor mortis remained dark. Present throughout the entire body. No visible marks were found on the body. 3 93.2 98.4-93.2/1.5= 3.5 Hours There were livor mortis patterns on the face in the nose and mouth area, in the lower legs and feet, on Rigor mortis was found to be present in the face and head. There was a green bruise on the upper left shin. © Copyright Michigan Virtual 2020 Revised 4/22/2020 Page 3

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