Crime Scene Diagramming and Reconstruction by Det. Mike Anderson

Crime scene diagramming and
reconstruction
Detective Michael S. Anderson
Unified Police of Greater Salt Lake County
Office 385-468-9821
Cell 801-884-9398

reconstruction
• Measuring methods
• A discussion about the methods
• Scene considerations
• Reconstruction methods
• Software's to be used & Equipment calibration
• Court testimony

reconstruction. Measuring methods
• There are several ways to document any crime
scene for purposes of preservation and
reconstruction.
• The first method has been around for all of us
the longest and that simply is hand
measuring.
• This can be an effective way to produce a scale
scene diagram, however this method needs
careful consideration in the measuring process

reconstruction. Measuring methods
• Since you will not be utilizing modern
technology in this process you will need to
measure on the X, Y, and Z axis yourself.
Careful recording of these measurements will
be crucial in the event you have a need to
produce a 3D scale diagram later.
• Processing this scene using the triangulation
or Coordinate method will produce the results
you are desiring.

reconstruction
• Example of Triangulation method

reconstruction
• The triangulation method simply works by
taking two measurements of any one point
from two known locations.

reconstruction
• The other option for hand measuring a scene
is the Coordinate method.

reconstruction
• The Coordinate method for many is a little
easier to deal with, and use. This method is in
some opinions easier if you aren't use to
measuring by hand.
• This method is just as accurate, so long as you
are accurate in the execution of the
measurements.

reconstruction
• To measure using the Coordinate system you
will measure off of two locations known as the
RP and the Baseline.
• Always a good idea when measuring by hand
or any other method for that matter to have
good scene pictures to help verify locations of
items identified for your diagram and eventual
reconstruction.

reconstruction
• The next method, and at one time a very
common way of diagramming a scene is the
use of Photogrammetry.
• Photogrammetry is a relatively inexpensive
way to diagram or measure anything by way
of using digital pictures.

reconstruction
• A simple explanation of Photogrammetry is
that by way of taking a particular set of
pictures of anything can result in a 3D
rendering of that item or scene, However
these pictures are very specific in nature, but
extremely effective.

reconstruction
• One of the most accurate and common ways
to survey any scene to date is the use of a
total station, or a series of total stations for
any scene which needs to be accurately
measured.
• Just like in Photogrammetry every point
recorded by the operator has the X, Y and Z
coordinate registered.

reconstruction
• Also like any of the previously mentioned
method this is as accurate as the user is.
• And is as detailed as the user wants to make it
be
• Any scene by way of this method can be
reconstructed in 2D, or 3D. Depending on the
needs of the case.

reconstruction
• There are many types of Total Stations on the
market.
• Sokkia
• Leica
• Trimble
• Nikon
• etc

reconstruction
• There are a couple ways to survey using a total
station
• One is direct shooting and logging the data
you survey directly into the gun itself
• The other is to survey into a data collector
using collection software which is similar to
the drawing software you already use.

reconstruction
• From a law enforcement perspective its my
belief that surveying by way of a data collector
is the best practice
• For the most part law enforcement officers
aren't professional surveyors, and therefore
the likely hood of a costly mistake can, and
will increase.

reconstruction
• The fact of the matter is this method gives us
the best chance at good results.
• By using a data collector you have the
advantage to see the collected data as you go.

reconstruction
• Having the ability to see your scene as it is
measured gives you the advantage of seeing
where things are missing, as well as a major
advantage by increasing the overall accuracy.
• If you are already surveying without a data
collector and you are comfortable doing it this
way then no worries
• Do what is familiar, and what you are
comfortable with

reconstruction
• And one of the newer methods to all of us is
the use of 3D laser scanners.
• There are several scanners available now
• The two most commonly known and used at
this time are the Leica scan station.

reconstruction
• And the other is the FARO 3D laser scanner.

reconstruction
• This method of measuring is not only the
future, but it is our present.
• There are numerous Law Enforcement
agencies from coast to coast that have
embraced 3D scan technology.
• This is the most accurate method available
right now for us to measure a scene.

reconstruction
• And it’s the best way to preserve a scene for
life.
• The laser scanner to explain it simply is
mapping and measuring everything that your
eye sees.

reconstruction
• As you look at these images realize that the
images are produced by laser mapping data.

reconstruction
• Laser scanning can be set up to take millions
of points per minute.
• How long would it take us to survey a million
points by hand measuring, Photogrammetry,
or even our total station’s?
• Laser scanning works much in the same way
as a total station does. We set up and we scan.
When we do this we have known common

reconstruction
• reference points ahead of us so that scans can
be merged together to create a single scan or
survey product.
• No matter how you are mapping and
diagramming your scene .
• The most important thing is that you know
how to explain the work that is done.
• And that the work done is accurate and
correct.

reconstruction. Crime scene
considerations
• Wherever he steps, whatever he touches, whatever he leaves, even unconsciously,
will serve as silent evidence against him. Not only his fingerprints or his footprints,
but his hair, the fibers from his clothes, the glass he breaks, the tool mark he leaves,
the paint he scratches, the blood or semen he deposits or collects - all these and
more bear mute witness against him. This is evidence that does not forget. It is not
confused by the excitement of the moment. It is not absent because human
witnesses are. It is factual evidence. Physical evidence cannot be wrong; it cannot
perjure itself; it cannot be wholly absent. Only its interpretation can error. Only
human failure to find it, study and understand it, can diminish its value.
• Kirk, Paul,
• Crime investigation,
• John Wiley & Sons Canada, Limited, 1953

considerations
• When we are just entering or we have been in
the scene for a time, we need to always be
mindful of the situation
• What is at our feet at all times, how many
evidentiary, or potential evidentiary items
have we stepped on, kicked, or destroyed
while we were present in a scene.

considerations
• Every time we become complacent in a crime
scene the potential to contaminate a key piece
of evidence increases
• Losing a case to a situation such as this is not
likely something any of us want to face.
• So what are the proper steps and
considerations we should make while the
crime scene is processed and the scene is
measured or surveyed

considerations
• Before measuring of the crime scene begins, the
scene as it sits should be documented.
• The best way for this is good proper overall
pictures, as well as a good walk through and
surrounding video.
• The simple reason for this is to have record of the
location of everything in the scene in the event
something does get moved, or even needs to be
moved intentionally for any reason

considerations
• In cases where something needs to be moved
it is a good idea when possible to mark the
location of the item to be moved as well as
pictures and video of the item prior to
movement
• When possible an actual survey measurement
of an item being moved should be taken prior
to any movement, but that isn't always
possible

considerations
• Sometimes we just need to be flexible in how
things are done, but we should never veer
from what needs to be done
• Corner cutting and unwillingness to do the
work is never excused in these matters

considerations
• Much of this process is going to be dictated by the
individual agencies policies and procedures.
• However minimizing any scene to outside influence will
always be the best practice.
• Limiting the possibility for evidence to be spoiled or
tampered with is a desired result.
• Having control of the scene is also important. simply
because a ranking officer shows up on scene and wants
to go inside and look around isn't a good enough
reason to enter. Remember it is you who has to testify
to this scene and its validity not the lookie loo
administrator etc.

considerations
• Once the scene has been processed and evidence
has been identified, the scene should then be
marked.
• This can be done by way of yellow evidentiary
markers, or what ever marking process your
agency has adopted.
• At this time the scene should now be re
documented by way of pictures and video
• It is also a good idea to complete a field sketch of
the scene.

considerations
• This process helps to validate that the scene
has not been changed from first entry.
• Once the pictures and video process has been
completed for the second time, you have now
reached the time to document the scene.

considerations
• From here the process really depends on what
your method of documentation is going to be.
• For instance does your agency prefer to collect
all the identified evidence within the scene
prior to the measuring and documentation
process?
• If so there are some things to really consider
here.

considerations
• By measuring a scene without the evidence still in
place, all your measuring is the location of the
evidence markers now.
• And is not necessarily the actual location of the
identified evidence.
• So does this matter?
• Well it may. Again the fact is you are the collector
of this data, and it will be you who has to testify
to the validity of the measured data regardless of
how the measurements were taken.

considerations
• Again individual agency policies will have the
final say in how this is completed, however it
is a good idea to always measure with the
placards or markers and the evidence still in
place.

considerations
• Remember two of our current methods of
scene measuring are depicting the scene in a
photo type manner such as 3D scanning and
Photogrammetry. From these two methods
alone anyone can see that evidence itself is
missing during the measuring process.

reconstruction. Some reconstruction
methods
• There are a few things to consider when
reconstructing a crime scene.
• First is what are you wanting, or needing to
show in this reconstruction?
• Many times simply showing the scene in a top
down 2D format, or view is all that is needed.
• Many times these diagrams are simply being
used to take measurements of evidence of
location, and items.

methods
• Or they are used to show an overhead view of
the scene and it’s evidence.
• If a 2D drawing is all that is necessary or needed
then we simply need to plug our measurements
into our drawing software.
• Rather this is done by inputting hand
measurements, or we are inputting that data
through a hand held device such as data collector
from a total station survey, or point cloud data
downloaded from a 3D scanner.

methods
• Either way the source of the data really
doesn’t matter.
• Once this data is in place a simple 2D drawing
can now be completed by way of connecting
the line points, and dropping in place the
evidence and the related placard numbers.
• These 2D drawings can be as simple as a black
and white line rendering.

methods
• To an elaborate depiction using colors and
textures.
• No matter how detailed you want to be the
most important thing in any drawing is going
to be the accuracy, and reliability of the
producing data.

methods
• Elaborate scene drawing

methods
• Simple scene drawing example

reconstruction. Software options.
• To create these drawing you will need some
type of software to achieve this.
• So what software to use?
• The fact is there are many choices, and the
best one for you, is for you to decide.
• Do your research when it comes to software.
What are your needs going to be, and what
are your capabilities to collect and use this
software?

• There is no reason to spend thousands and
thousands on a software that does many things
that you don’t have the capability to utilize.
• You also don’t want to buy an inexpensive lesser
software that doesn’t take care of your needs
based on your capabilities.
• Too many times especially in law enforcement we
get stuck in the mind set that if we can do it
cheaper then that is our route.

• However it does no good to not be able to
conduct your business as needed.
• So spending the extra to do what is necessary
is the best option even though it will cost
more.

• So what is out there?
• Many of us are users already of this company’s
product, crime zone crash zone has been
around a long time.

• ARAS 360

• Visual Statements FX3

• EDGE FX

• Autocad

methods
• You also may have a need to have something a
little more elaborate.
• Such as representations in 3D
• Or scene fly through representations etc.

methods
• 3D drawing views or videos can allow you to
place a judge or jury in the scene.
• even if the scene no longer exists.
• These views can also be extremely helpful in
an investigation
• They can help an investigator see what the
actual view would have been for a witness or
victim etc.

methods
• Bullet trajectory example from FARO scan data

methods
• Scene fly through examples
• These examples were created in the SCENE
software. This is the FARO cloud managing
software specific to FARO.

reconstruction. Court Testimony.
• At the end of the day what we are after is a
suspect conviction.
• All the work done by the investigators, the
crime scene personnel, and the prosecutors is
to build a strong prosecutable case.

• So as the documenter of the scene, it is our job to
do a good and accurate rendering of the scene,
the evidence, and anything else that needs to be
captured.
• Making sure that all of your measuring
equipment which you rely on is at a minimum
annually cleaned inspected and calibrated.
• It doesn’t matter if you are using a rolling tape
measure to a laser scanner. This cannot be
skipped.

• The validity of the data is going to be the first
line of attack for a defense attorney.
• Always have on hand with you in any court
proceeding the documentation of your
measuring instrument and its calibration.
• Do not find yourself trying to explain this on
the stand without being able to produce it
when asked to.

• And always remember you only know what you
know.
• Always stick to the facts as you know them to be.
• If you don’t know something that is ok, never
assume to know facts when you don’t.
• And always tell the truth even though a truthful
answer may be hurtful to the case.
• Your career, family, credibility and livelihood are
far more important than this case.

Crime Scene Diagramming and Reconstruction by Det. Mike Anderson

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (20)

Similar to Crime Scene Diagramming and Reconstruction by Det. Mike Anderson

Similar to Crime Scene Diagramming and Reconstruction by Det. Mike Anderson (20)

Recently uploaded

Recently uploaded (20)

Crime Scene Diagramming and Reconstruction by Det. Mike Anderson

Editor's Notes