Chapter 2 notes

Physical

Informational

Behavioral

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Phase 1 the antecedent phase

perpetrators behavior prior to the crime is what is important.

Are there any indications of prior planning.

Pre-crime stressors? Changes in mental or emotional state, job loss, arguments, financial problems…

Phase 2: the homicide

how is the victim selected?

Why this victim?

Method of abduction?

What did he do to the victim and how?

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Phase 3: the body disposal

the offender now has to deal with the consequences of his actions which will result in more displayed behavior.

Altering the scene to misdirect police

how is the body transported? Why this location? Was the body concealed? Was the body posed? Was the body mutilated?

Phase 4: post-offense behavior

what did the offender do after altering the scene?

Lee, get sick, do alcohol or drugs, failed to show up for work or school, return to the site?

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the scientific method for investigators

only methodology that is nearly impervious to scrutiny from fellow experts

guidelines:

1. Judge is gatekeeper: assuring that a scientific expert is an expert rests on the trial judge

requires that the testimony is based upon sufficient facts or data and

testimony is the product of reliable principles and methods and

witness has applied the principles and methods reliably to the facts of the case.

Relevance and reliability

an expert’s testimony must be relevant to the task at hand and is based on a reliable foundation

scientific knowledge equals scientific method/methodology

must demonstrate that it is of sound scientific methodology derived from the scientific method.

Factors relevant

the scientific methodology is the process of formulating hypothesis and then conducting experiments to prove or falsify the hypothesis and provided a non-dispositive, nonexclusive, “flexible” test for establishing its validity consisting of: empirical testing, subjected to peer review and publication, known or potential error rate, and the degree to which the technique is generally accepted by the relevant scientific community.

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While you could argue that these standards only apply to crime scene technicians or crime lab personnel, investigators must maintain the same level of accountability.

There’ve been several cases where convictions have been overturned because law enforcement officials gave testimony based solely upon their proceeding experience and without further validation of their opinions

the scientific method for investigators

1. obtain from witnesses the accounts of what happened
2. based on these accounts anticipate questions you will be asked by others so you can properly collect and record the physical evidence.
3. Collect and record the physical evidence.
4. Formulate hypothesis about the events that occurred and anticipate the questions you will be asked.
5. Determine whether or not the witness statements are consistent with the physical evidence; gather more information or evidence as needed.
6. Through the process of verifying witness statements, admission/confessions, consider the evidence at hand and disprove as many hypothesis as you can.
7. Formulate an assessment (final hypothesis) to a reasonable degree of certainty, recognizing the existing limitations.

Investigators frequently tend to focus on a single-minded course of action without regard or consideration for other possible avenues of explanation.

All other possibilities in an investigation should be eliminated in order to make the final conclusion more powerful.

Base your hypothesis upon sufficient facts and data and eliminate other explanations for the crime by pairing the physical evidence with investigative beliefs.

Never try to make evidence fit a theory as this will quickly invalidate the investigative process.

Regardless of the strength of evidence very little in investigations is absolute and we can never be certain of how past events occurred.

Two important investigative processes:

1. verify witness statements and historical data with comprehensive known facts and circumstances to validate or disprove previously discovered information.
2. Falsify circumstantial evidence: in other words it has to stand up to sound scientific principles

all investigative efforts should be used to disprove your hypothesis of how the crime occurred in this will either affirm or reject your hypothesis.

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