Crime Scene Procedures:

Primary scene - Where crime occurred

Secondary scene - Other location where evidence can be found

SOCE - Scene of crime examiners

Securing the Crime Scene:

• Crime scene secured and isolated using preservation tape, large enough to preserve all areas of the scene. To prevent unauthorized access. Record kept of all personnel entering and exiting scene

Crime Scene Search:

• To retrieve maximum amount of evidence via professional and methodical approach

• If trace of evidence cannot be preserved properly for lab examination, no technical expertise or equipment at the lab can save the evidence

Preliminary Survey:

• Done to figure out the types of evidence that should be looked for. Nature of scene indicates the type of evidence that may be acquired

• Physical evidence: Any object trace can establish that a crime has been committed or link a crime to victim / perpetrator

→ Can range from large objects to microscopic traces

Recording the scene:

• Everything recorded in its untouched state

• Physical evidence is photographed where found

• After measuring the scene it is all sketched

• In serious assaults / murders position of body, indicators of struggle

• Accurate detailed notes made including time when each item was discovered by who and how it was packaged

• Video recordings done sometimes but need to be transcribed into a written document

Crime Scene search methods:

1. Point to point - Movement following a chain of objects which are obvious evidence

2. Spiral search - Carried out by a single person walking in a circular fashion from the outermost boundary towards the central point of the cordoned off area. (Not started in the center as viral evidence may be destroyed walking towards central)

3. Zone Method - Entire scene divided into zones which are searched individually. (Most suitable when searching for a small object)

4. Strip method - Area divided into strips 1m wide. Searchers examine each strip separately until a thorough search has been conducted of entire area ( large outdoor area)

5. Grid searching - Advanced strip search, searchers doubling back perpendicular across the area searched.

→ More time consuming but very methodical and thorough (searched from two different view points) each square assigned to a number or letter

Retrieving Evidence:

• Packaging materials and labels should be available before starting the search. Make detailed note of position and appearance before taking.

• Each item should be labeled before proceeding to the next item. Important item reaches appropriate expert in same region it was discovered in

• Avoid contamination

Contamination:

Happens when traces of evidence transfer to the scene after the crime was committed before the analysis

1. Any person at the scene transfers their DNA, hair, clothing Fibers

2. Person may be contaminated through contact wing an unclean surface

Primary transfer - Direct contact between items from different aspects of the case or between victim and suspect after the incident

Secondary transfer - Same member handling items from different aspects of a case

Avoiding contamination:

• Wearing clean disposable over garments. gloves and masks until all items packaged and sealed

• Never talk over an exposed item

• Examination surfaces should be thoroughly cleaned and a clean plastic sheet/paper as a protective barrier

• Items should be packed, sealed and labelled before removal and should not be reopened

• Different police should deal with different sides of the case

• Victims and suspects should not be transported in the same patrol car or interviewed in the same room

• Samples of liquid accelerants should be packed and stored separately from samples of fire debris

Labelling Items:

Clear label with the following information:

• Police district concerned

• Nature of occurrence or crime

• Name of injured party

• Name of accused / suspect

• Brief description of items and where and when found

• Identifying number assigned by officer in charge of case

• Name of person who found the particular item

• Date

Evidence Containers:

• Manila envelopes, screw cap glass vials, sealable plastic bags used for the collection of most trace of evidence

• Airtight containers should not be used for bloodstained materials (paper bags used instead)

• Charred debris should be sealed in an airtight container to prevent evaporation of volatile petroleum residues

• Glassine Evidence envelopes used for hairs, fibers, glass shards, paint tips (eliminates static electricity, breathable + transparent)

• Clear tubes with rubber cap and a styrene inner cushion used for sharp objects

• Lined all metal cans with air tight lid used for collection of evidence with accelerant contamination

Standard / Reference and control sample:

Comparison of evidence (eg the paint of a suspects car and the paint of the car used in a hit and run)

• Control samples are often required

Maintaining Chain of custody:

• Record kept of all who handled, transported or examined evidence

• Any person involved in handling the evidence will be required as a potential witness. Each witness should be in a position to give evidence as to what they have done with the item along with the dates

• Exhibit officer - prepare a chart recording movement of each item

Processing a CS with no search warrant:

Can only happen in extreme cases: prevent loss of evidence, arrest is being made, consent is given

→ Otherwise search deemed illegal and all evidence collected inadmissible