Collection and Preservation of Physical Evidence

Forget everything you’ve seen!

Scene management at it’s best

What we will cover… Crime Scene Management Collection of evidence Methods & materials Photography Diagramming Fingerprints Blood evidence Collection Scene testing DNA Contamination Testing methods Bloodstain Patterns Recognition Footwear evidence Photos & casts Case Studies

Why physical evidence?

Crime scene management Usually neglected…until it’s too late No second chances Cases fall apart at the basics Make ‘em scatter…take pictures!!! Shows control from the beginning

How many of them wrote a report?

Flash goes off…and away they go!

Stages of a crime scene The stages help you stay organized Your documentation and search will be more organized It’s one less thing for you to worry about

Preparation You’re doing it now! Training Equipment Commitment – from you and the organization Court decisions

Preparation All this should be done prior to arriving at the scene – if possible Pre-planning assignments/equipment Safety of personnel Assignments based on training/aptitude and experience ERT Prolonged searches Rest of personnel Maintaining the scene

Preparation Multiple jurisdictions involved Expertise available from other departments Equipment available from other departments

Approach Notes Discarded or disturbed items Time dispatched Time arrived Who’s there upon arrival Weather conditions Discarded or disturbed items Safety issues (your own and the scene)

Secure and Protect Too large is better than too small What has been done to secure it Is it enough? Crime scene log Everybody that goes in gets written down The officer maintaining it also makes an entry Too large is better than too small

Secure and Protect Use of protective equipment (shoe covers, Tyvex suits) by those who enter Notes…and more notes ONE person in charge to relay information Command post – to keep “them” away from the scene

Preliminary Survey Walk through Go with one of the first officers there Preliminary photos – digital Keeps the # of people entering to a minimum Start a trash container – for trash you generate

Preliminary Survey ID & protect transient evidence Personnel and equipment needs Determine what has been changed by the first responders Develop a general theory of the crime based on this review and information provided by others Compare what you are seeing with what is being provided by witnesses

Physical Evidence Possibilities Transient evidence – changes with time and is easily lost A staged scene? Most transient to least transient What may have been moved by mistake Specialized techniques needed?

Narrative Description DO NOT collect evidence at this point Go from general to specific Photos can help to supplement your notes but must not replace them Weather, lighting, parked vehicles, wet items, items apparently missing, as you found it – do not put items back in place

Written, audio or video Operable? Written notes should be retained May need to be provided through discovery Audio Video – use of sound Radio traffic Comments by others Humor

Photography Rule of three Overhead photos DPW and other resources Overall Intermediate Close up Overhead photos DPW and other resources

Photography Photos with and without scale Views of witnesses Photos are two dimensional – not likely to be able to determine distances Take plenty… Some evidence can only be recorded photographically Need for specialized photographic techniques

Diagrams Rough sketch Finished sketch Measuring methods Not to scale Retained Finished sketch Drawn to scale Concern for appearance Measuring methods

Measuring Methods Baseline Triangulation Requires a straight line Measurements made off baseline at 90 degrees Triangulation Two fixed points

Conduct Detailed Search Record & collect physical evidence Specialized search patterns Master Evidence List Mark the item or the package Minimize handling Try to have one person do this

Record & Collect Physical Evidence Paper bags or paper containers Avoid plastic if possible Mark the seal half on the tape and half on the package

Record & Collect Physical Evidence Get in the habit of putting your initials, the date and time on items you collect This helps you to stay organized and methodical Mark the package – not the item itself

Record and Collect Physical Evidence Marking Initials/ date/ time ASAP – on the item itself or the package. The package is usually a better choice. Recording Master evidence list KMM-1 One bullet casing… CMS-2 Victim’s plaid shirt…

Master Evidence List

Specialized Search Patterns Line search Grid search Spiral search Coverage of large area

Grid Search Pattern

Record and Collect Physical Evidence Evidence is packaged AND sealed at scene Package to minimize movement Collection of “known” or “alibi” standards should also be done now You have ONE chance to do this

Final Survey Get out Take a break Review what you’ve done Think of the overtime Review what you’ve done All equipment out Compare notes with other investigators

Final Survey All evidence is accounted for All equipment is accounted for Do we need to keep this scene?

Release the scene Everybody needs to know this is going to happen Autopsy results? Security of scene? Notify person assuming control what processing has been done

Release the Scene Document the release Date and time To whom By whom Re-entry will likely require a warrant The person in charge of the investigation MUST be aware this is being done

Back to basics… By following this general outline you ensure that the basics are covered Many high profile cases are criticized at the basic level – crime scene management A high profile case can happen anywhere, at any time