Guiding Principles for Scene Investigation and Reconstruction 

1 OSAC 2021-N-0015 

2 Guiding Principles for 

3 Scene Investigation and 

4 Reconstruction 

5 Crime Scene Investigation & Reconstruction Subcommittee 

6 Scene Investigation Scientific Area Committee 

7 Organization of Scientific Area Committees (OSAC) for Forensic Science 

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Guiding Principles for Scene Investigation and Reconstruction

8 Draft OSAC Proposed Standard

9 OSAC 2021-N-0015

10 Guiding Principles for Scene

11 Investigation and Reconstruction

12 Prepared by 

13 Crime Scene Investigation & Reconstruction Subcommittee 

14 Version: 1.0 

15 March 2021 

16 Disclaimer:

17 This OSAC Proposed Standard was written by the [insert subcommittee or other unit name] of 

18 the Organization of Scientific Area Committees (OSAC) for Forensic Science following a 

19 process that includes an open comment period . This Proposed Standard will be submitted to a 

20 standards developing organization and is subject to change. 

21 There may be references in an OSAC Proposed Standard to other publications under 

22 development by OSAC. The information in the Proposed Standard, and underlying concepts and 

23 methodologies, may be used by the forensic-science community before the completion of such 

24 companion publications. 

25 Any identification of commercial equipment, instruments, or materials in the Proposed Standard 

26 is not a recommendation or endorsement by the U.S. Government and does not imply that the 

27 equipment, instruments, or materials are necessarily the best available for the purpose. 

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Guiding Principles for Scene Investigation and Reconstruction

28 Foreword 

29 This standard was developed to provide guidance to scene investigators and scene

30 reconstructionists a baseline for the guiding principles for scene investigation and reconstruction.

31 This document has been prepared by the Organization of Scientific Area Committees (OSAC) for

32 Forensic Science Crime Scene Investigationand Reconstruction Subcommittee.

33 Keywords: Crime scene, reconstruction, chain of custody, ethics, bias, safety, contamination,

34 validity, reconstructionist, scene investigation

35 Abstract: This document provides minimum standards and recommendations for practicing

36 scene investigation and reconstruction. This document provides guiding principles for the

37 identification, documentation, collection, preservation of physical evidence, and scene

38 reconstruction.

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Guiding Principles for Scene Investigation and Reconstruction

39 Table of Contents

40 1 Scope............................................................................................................ 3

41 2 Normative References...................................................................................... 3

42 3 Terms and Definitions...................................................................................... 3

43 4 Guiding Principles.............................................................................................. 4

44 4.1 Legal Considerations....................................................................................... 4

45 4.2 Personnel Safety............................................................................................... 5

46 4.3 Scientific Reliability and Validity............................................................................ 5

47 4.4 Preserving Context ............................................................................................ 6

48 4.5 Maintaining Evidence Integrity ............................................................................. 6

49 4.6 Transparency and Ethics....................................................................................... 6

50 4.7 Managing Bias................................................................................................... 7

51 5 Annex A (informative) Bibliography........................................................................ 8

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Guiding Principles for Scene Investigation and Reconstruction

52 Guiding Principles for Scene Investigation and Reconstruction

53 1 Scope 

54 This standard describes the minimum general standards of practice or guiding principles for

55 practicing scene investigators and reconstructionists. These Guiding Principles establish a 

56 framework for expected behavior and for decision-making. These principles include legal

57 considerations, personnel safety, scientific reliability and validity, preserving context, maintaining

58 evidence integrity, transparency and ethics, and managing bias.

59 2 Normative References 

60 There are no normative documents.

61 3 Terms and Definitions 

62 For purposes of this document, the following definitions and acronyms apply.

63 3.1

64 crime scene investigation

65 CSI

66 A scene investigation that involves a potential criminal act.

67 3.2

68 crime scene investigator

69 CSI

70 An individual, however named, who is responsible for performing elements of a scene 

71 investigation that involves a potential criminal act. 

72 3.3

73 crime scene reconstruction

74 CSR

75 A scene reconstruction that involves a potential criminal act. 

76 3.4

77 crime scene reconstructionist

78 CSR

79 An individual, however named, who is responsible for performing elements of a scene 

80 reconstruction that involves a potential criminal act. 

81 3.5

82 scene

83 A place or object that is subject to and/or requires forensic examination. (ISO/FDIS

84 21043-1:2018[E])

85 NOTE A crime scene is a common description of a scene where a presumed crime has been

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Guiding Principles for Scene Investigation and Reconstruction

86 committed. The scene can be a person or an animal.

87 3.6

88 scene investigation

89 An examination of a scene to locate, document, collect, and preserve items of potential 

90 evidentiary value. 

91 3.7

92 scene investigator

93 An individual, however named, who is responsible for performing elements of scene 

94 investigation. 

95 3.8

96 scene reconstruction

97 The utilization of information gathered from the investigative process to develop or eliminate 

98 possible explanations for how an incident occurred. 

99 3.9

100 scene reconstructionist

101 An individual, however named, who is responsible for performing elements of scene 

102 reconstruction. 

103 4 Guiding Principles 

104 Each scene is unique and requires scene investigators and reconstructionists to continuously

105 evaluate how to proceed with processing in a manner that is safe and best preserves the evidence

106 and its context. All decisions made by a scene investigator or reconstructionist before, during, and

107 after a scene is processed should consider the following:

108 1. Legal Considerations

109 2. Personnel Safety

110 3. Scientific Reliability and Validity

111 4. Preserving Context

112 5. Maintaining Evidence Integrity

113 6. Transparency and Ethics

114 7. Managing Bias

115 Scene investigation and reconstruction are led by general guiding principles. Though all the guiding

116 principles listed in this document are important, some circumstances could require a scene

117 investigator or reconstructionist to give greater weight to one principle over another. A decision to

118 deviate from a guiding principle shall be documented and explained.

119 4.1 Legal Considerations

120 Scene investigators and reconstructionists shall conduct themselves with the expectation that their

121 work may be used in every step of the legal process, and therefore shall ensure that they comply

122 with applicable legal standards including those of search and seizure.

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123 4.2 Personnel Safety

124 Scenes can present a wide variety of physical, biological, chemical, and situational hazards with a 

125 level of personal risk of injury, illness, or exposure almost always present. Personnel shall not be

126 exposed to an unreasonable level of risk to personal safety and shall be provided with the

127 equipment and training necessary to mitigate risks.

128 a) Scene investigators and reconstructionists shall have appropriate personal protective

129 equipment (PPE) to mitigate hazards presented by the scene and by any processing tools,

130 equipment, or reagents used.

131 b) Scene investigators and reconstructionists shall be trained in the proper use of PPE. Some

132 forms of PPE may require fit testing or certification for safe use.

133 c) PPE protocols shall include:

134 i) Hazard assessment and PPE selection.

135 ii) PPE cleaning, maintenance, decontamination, and storage.

136 d) PPE considerations should include, but not limited to, protection of eyes and face, head, foot

137 and leg, hand and arm, body (torso), respiratory system, and hearing; and protection

138 against, falls, and drowning.

139 4.3 Scientific Reliability and Validity

140 Scene investigators and reconstructionists shall use scientifically reliable and valid methods,

141 practices, and analytical procedures.

142 a) Methods, practices and analytical procedures shall be based on best practices,

143 peer-reviewed studies, and/or validated techniques prior to use on scenes.

144 b) When applicable, methods, practices and analytical procedures published in the OSAC

145 Registry shall be employed.

146 4.4 Preserving Context

147 Scene investigators and reconstructionists shall document a scene in such a way that it preserves

148 the context of the evidence to ensure others can later understand not just what was collected, but

149 also where, how, and in what condition it was found.

150 4.5 Maintaining Evidence Integrity

151 Scene investigators and reconstructionists shall take appropriate steps to maintain evidence

152 integrity by preventing contamination, tampering, alteration, or loss of evidence. Procedures and

153 documents shall be utilized to account for the integrity and possession of evidence by tracking its

154 handling and storage from its point of collection to its final disposition.

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Guiding Principles for Scene Investigation and Reconstruction

155 4.6 Transparency and Ethics

156 The work of a scene investigator and reconstructionist generates the underlying basis for all

157 subsequent analysis of the scene. The scene investigator and reconstructionist shall provide

158 documentation and testimony of the scene that clearly represents its initial condition, their actions

159 on-scene, and any other relevant factors.

160 a) If an action by an investigator will intentionally deviate from, or set aside, one of the

161 principles, the circumstances and justification shall be fully documented.

162 b) Upon discovery of unintentional deviations, errors, omissions, or acts of nonconformance

163 with the principles, the circumstances shall be fully documented.

164 c) While an enumerated Code of Ethics is beyond the scope of this standard, scene

165 investigators and reconstructionists have professional duties that they are bound to and

166 shall execute. These include the duty to:

167 i) remain competent in a wide range of scientific fields.

168 ii) be as objective as reasonably possible.

169 iii) act thoroughly and to produce results and conclusions within the scope of the

170 expertise of the individual practitioner.

171 4.7 Managing Bias

172 Scene investigators and reconstructionists are uniquely positioned at the intersection of law

173 enforcement and scientific investigations, and shall ascertain the facts, without regard to external

174 influences.

175 a) Scene investigators and reconstructionists shall take steps to mitigate effects of cognitive

176 biases on their work.

177 b) A scene may be full of potentially biasing influences. Decisions made by scene investigators

178 and reconstructionists depend on and require some contextual information and hypothesis

179 formulation, which guide them in their search for evidence and/or analysis. It is critical that

180 hypotheses are well-determined, as they can lead to identification and collection of

181 important evidence or, alternatively, mislead the investigator.

182 c) As with forensic laboratory analysis, the scene investigator and reconstructionist shall

183 remain as independent as possible from non-scene-related and potentially biasing case

184 information (e.g., suspect or victim criminal history).

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185 Annex A

186 (informative)

187 Bibliography

188 1] Bowen, Robin. Ethics and the Practice of Forensic Science. 2

nd Ed. CRC Press, 2018.

189 2] Dror, Itiel E. Cognitive neuroscience in forensic science: understanding and utilizing the

190 human element 370 Phil. Trans. R. Soc. B http://doi.org/10.1098/rstb.2014.0255, August

191 2015.

192 3] Houck, Max and Siegel, Jay. Fundamentals of Forensic Science. Elsevier Academic Press, 2006.

193 4] ISO 21043-1:2018(E) Forensic sciences- Part 1: Terms and definitions.

194 5] Lucas, D. The ethical responsibilities of the forensic scientist: Exploring the limits, J. Forensic

195 Sci., 34(3), 719–729, 1989.

196 6] National Forensic Science Technology Center. Crime Scene Investigation: A Guide for Law

197 Enforcement [supported under cooperative agreements by BJA, NIJ, and NIST]. NFSTC, 2013.

198 1

199 7] U.S. Department of Labor Occupational Safety and Health Administration. Personal

200 Protective Equipment [OSHA Publication 3151-12R],

201 https://www.osha.gov/Publications/osha3151.pdf, 2004.

202 8] United States Department of Labor, Occupational Health and Safety Administration.

203 Standard 1910 Subpart I Personal Protective Equipment [Occupational Health and Safety

204 Standards]

2

205 1 Available free at https://www.nist.gov/sites/default/files/documents/forensics/Crime-Scene-Investigation.pdf

206 2 Available at https://www.osha.gov/laws-regs/regulations/standardnumber/1910

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