Qualitative Theory for Crime Scene Analysis

Intro

goal of crime scene reconstruction (CSR): identify as many objective facts about what happened and in what order as possible

debate on whether procedures are necessary or not in terms of analyst actions

trying to explain unique event, so there is no objective standard, difficult to mitigate bias

little effort has been made to refine crime scene reconstruction (CSR) theory in criminal investigation because a large part of it is common sense

theory development occuring in failure analysis that could be applicable to CSR

Multi-Linear Events Sequencing (MES) - precursor to failure analysis

paper question: can a more-detailed theory for CSR be developed?

Purpose

common sense is insufficient a a procedure

define our beliefs so they can be challenged

Axiom 1

axiom 1: every object is unique

object - any 3D artifact encountered at a scene

if any one axiom can be show to be invalid, the theory itself is invalid as written

object remain consistent with themselves unless converted into something else

Axiom 2

axiom 2: while it exists, an object must exist continuously in both time and space

all objects have three spatial dimensions

current physical theories define space and time as continuum in which events occur

world-line: set of continuous moments of existence for an object describing its path through space-time

Axiom 3

axiom 3: every point of an object's existence is connected to some other point of its existence

from one point to a next in space-time, and object has a continuous path through time and space through all four dimensions

the world-lines of constituent pats are connected to the object's original world-line

Axiom 4

axiom 4: for any temporal value of a world-line that follows some other value of the object's world-line, that temporal value must be greater

to current understanding, time is unidirectional, so temporal values only increase along a world-line

Axiom 5

axiom 5: every value of an object's world-line is unique

object can be spatially stationary, but will always be in constant motion through time

objects can only exist in one place at any one time, so the temporal value cannot be repeated

every value of an object's history has coordinates t, x1, x2, and x3 that are completely unique to that moment

Axiom 6

axiom 6: to create an action (to produce some change in sate of an object) there must be a cause

event: instantaneous moment in object's history

actions are series of events that produce a change of state

Newton's 1st Law: a force is needed to induce a change in state of an object

forces cause accelerations (changes in velocity)

any change in state of an object is due to acceleration

Axiom 7

axiom 7: effect cannot precede cause

establishes temporal order between two things

Axiom 8

axiom 8: an action (a change in state of an object) can only occur as a function of some interaction)

need force to cause acceleration

force on an object may be an interaction with another object or a fundamental force influencing the object

Axiom 9

axiom 9: in order to interact, the spatial and temporal existence of objects must overlap in some way - or - the object must exist spatially and temporally within the influence of a fundamental force

if the object changes state because it interacts with a second object, the two objects must have come in contact with one another

if the object changes state because it interacts with a fundamental force, the object must exist somewhere in space-time where the force is involved

an object's proximity to a fundamental force may or may not be relevant depending on whether the force is location-specific or not

Axiom 10

axiom 10: every action has at least one prior action that influenced it

all object world-lines are connected; objects cannot simply come into being

all actions are influenced by a previous set of actions

Axiom 11

axiom 11: any two actions associated to a given incident have a unique causal relationship

the inability of the analyst to identify causal relationships does not mean they do not exist

All actions associated with a given incident share either a direct or a hierarchical/ancestral causal relationship

direct causal relationship: A causes B

hierarchical/ancestral relationship: both part of a unique chain of events

each interaction can make the chain diverge and make two independent paths, after which no causal relationships exist between the different branches; however, they still share ancestral causal relationships

spatial or temporal proximity alone does not create causal relationships

contextual bias: surrounding factors influence your perception of facts

Axiom 12

axiom 12: any given set of actions will have a unique temporal relationship

exact relationship - can establish specific time for action

ambiguous relationship - recognize the relationship between two things, but not necessarily the exact temporal point; aka relative chronology

Conclusion

the axioms are sufficient to describe the world accurately enough for our purposes, whether as axioms or theories

if there is enough data, CSR can understand some of the actions and relationships present

axioms provide a degree of scientific backing for CSR conclusions beyond analyst experience and training

Source: Gardner, R. M. (2016). A qualitative theory for crime scene analysis. J Asssoc Crime Scene Reconstr, 20, 45-55.