As trained crime scene technicians you are expected to develop the maximum amount of information from the crime scenes. This information is developed by processing the scene for physical and testimonial evidence. The testimonial evidence is the interpretation of the facts in the crime scene.
Lets take an armed robbery at a convenient store as an example. The store clerk is approached by an armed suspect who robs the store and flees from the store, jumps into an awaiting car and escapes from the scene. The store clerk gives the investigators a statement as to what has occurred. This statement will include what the store clerk observed. Their observations will include the description of the suspect and vehicle. This is testimonial evidence. They will testify in court as to their observations, the same as a trained crime scene technician will testify to his interpretations. However his interpretations are based on facts that he will have to prove in court. This proof will be based on physical evidence and the interpretation of that evidence.
Lets carry this a little farther. You are called to a residential burglary where unknown suspects forced their way into a residence and stole items belonging to the victim. You examined the residence and find that the back door has been forced open with the use of a wide pry type tool. You know this to be a fact because of the size and shape of the toolmark. A closer examination of the toolmark reveals a blue paint transfer from the tool to the white wood door casing. Now you know for a fact that the tool used is a wide pry type tool that is either blue in color or has blue paint on it. Since this is the point of entry to the residence you exam the outside area around it. You discover a footwear pattern in the soil leading to the point of entry. This same pattern is evident on the door where the suspects had also kicked the door to force it open. Again you have factual evidence, the footwear pattern, to make this interpretation. You process this door and casing for fingerprints and discover cloth impressions. The cloth impressions would indicate that the suspects either had gloves on at this point or a cloth material over their hands. Just because you find cloth impressions at the point of entry don't assume that the suspect kept his gloves on all the time. You may find an item that he had to handle with both hands and discover that he had a glove only on one hand.
Inside the residence you observe the same footwear pattern as found on the door and in the yard. This pattern leads to every room in the residence that has obvious disturbance caused by the suspects, i.e., drawers pulled out and dumped, closets rifled, jewelry boxes dumped on the bed, and so on. This footwear evidence will lead you to interpret the direction that the suspect went inside the house. Finding different patterns of footwear impressions inside and out could tell you how many suspects were in the residence.
This procedure continues throughout the residence gathering physical evidence that will allow you to make factual interpretations of the crime scene. Unfortunately this information usually is not documented by the crime scene technician in his crime scene report. Documentation is made by notes, sketches and photographs. If you observe something in the crime scene then DOCUMENT IT!
How are you going to convince the judge or jury of your interpretations if you can't prove the facts as you observed them.
This is where most mistakes are made by the crime scene technician testifying in court hearings. They know what they saw but failed to properly document their observations.
There have been many cases "made" because of the documented interpretation of the scene by the crime scene technician. The following is an example of these cases.
CASE #1: Suspect in a business burglary denies any knowledge of the burglary. He then confesses to the investigators after he is told of the interpretation of the evidence found at the scene. The investigators told the suspect how he entered the business, that he was wearing cotton gloves with yellow fibers, what direction he went in the business, how he left and his footwear pattern was similar to what was found at the scene. This was all based on factual evidence from the scene. The suspect confessed because he thought he was video taped by a hidden camera at the crime scene. In his own words "No one would have known that (the interpretation) if you didn't have that hidden camera you would have never caught me."
CASE #2: The suspect in a brutal murder of his wife and child denied any knowledge of the crime. After being told of the interpretation of the blood spatter, how many times he struck the victims with the aluminum bat, and where he was standing at when he struck them, he confessed to the double murder.
CASE #3: Three brothers were home alone when according to the surviving brother one brother shot the other one and then shot himself. The scene was processed for evidence and the interpretation of the evidence indicated that the surviving brother was not telling the truth because the scene indicated that the shooting did not occur as was stated. After changing his story five times the surviving brother confessed to shooting both of his brothers just as the interpretation of the crime scene indicated.
You will be able to reconstruct the crime scene in court if you remember that the "reconstruction" is your interpretation of the factual evidence in the case. All facts or evidence in crime scenes are derived from the complete processing of the scene and the new "tools" we have to work with. These new tools are: Blood spatter and flight interpretation, Electro-Static Dustprint Lifter, Super glue fuming, portable lasers, and alternate light sources. These are only a few of the modern day advances in equipment and techniques for processing crime scenes. However, even with "miracle" tools and techniques, if the evidence and facts of the case are not documented you will not be able to prove your interpretation of the scene.
Remember to never assume or guess and always document your observations
by sufficient notes, photographs and sketches.
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