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Important note: This whole section has been compiled from books and
websites, with occasional help from people working in this field. Like the rest
of Deep Background (of which this is only a small part), this information is
designed for writers of X-Files fiction, and covers only those things that they
might be expected to need. It is not a comprehensive guide to the subject.
Crime Scene Protocol
This section covers crime scene protocol - who is allowed at a crime scene,
the order evidence is collected, who is in charge etc. Information on
what evidence is collected and how it is analyzed is given
Thanks to Jad for help with this section.
- Initial procedure
Upon arriving at the scene, the first priority is safety - making sure
there are no suspects hanging around. Then, if there are any wounded people,
first aid should be performed.
Then the first officer to respond to the crime scene immediately set up a
perimeter. That's the yellow crime scene tape seen all the time in the
X-Files. He keeps everyone, everyone, out of the crime scene until
the detective and the lab people get there. He takes whatever precautions are
necessary to preserve the integrity of the scene (this will in part depend on
the weather. In rain, obviously, the evidence may wash away, while in dry
weather it is different.)
He also starts a crime scene log. The log lists everyone who goes
past the perimeter and enters the crime scene, and records their name, the
agency they're with (if more than one are involved), and the reason they're
there. This log stays active until the last person leaves (which is nearly
always the crime lab people).
The officer also isolates all the witnesses, separately if he
- Planning strategy
When the detective gets there he waits for the crime scene investigator
(the one who will coordinate the forensic work) if he can. If not he will
proceed to tentatively look at the crime scene but that is all. He won't touch
or move anything, including the body until the investigator gets there. And
vice versa. When the detective and investigator are ready they do a
walk-through with the first officer to arrive on the scene (so he can tell them
if anything looks different from how it looked when he arrived). They discuss
various scenarios, and what looks like implicated evidence and what is
unrelated. They basically try to piece back together what happened and get a
This walk-through is essentially important. If possible, they actually walk
on ground that doesn't look as if it has any vital evidence upon it. When
going through doors etc they must be very careful not to disturb any vital
footprint evidence. The manuals suggest that they keep their hands in their
pockets to make sure no-one is tempted to touch anything.
No one has touched the body yet. The only people in there or around the
crime scene are the detectives and forensic investigator. Once that's done
they kind of go their separate ways.
- Collecting evidence
Overall photographs will be done first before anything is disturbed.
These always seem to be black and white on television, but in reality they are
color. In the past, crime scene photos were always shown as black and white
as it was considered that color was too gory and would shock juries in murder
trails and influence their judgment. Now, photos are done in colour, and
shown to juries in color.
As film is cheap, photographers are encouraged to take pictures from all
angles - whatever might be useful. Videos are sometimes used to.
It is also recommended that a sketch is done, as this can show the scales
and dimensions in a way that photography can't. This will just be a rough
sketch which can be turned into something better later on.
Then evidence collection starting from the outer perimeter and
moving in. Often they will do the doors first so that people can then come in
and out without disturbing vital evidence, but they may seal off the doors and
go straight to the body. This order is adhered to if the scene is small enough
that it won't take too long. If the scene is large, sometimes they may skip
and go right to the body so the detectives can take a look. However, nobody
touches the body until photographs are taken of the position and wounds that
The lab people dust for prints, take photographs, look for the murder
weapon, document blood spatters, collect trace evidence etc. This will be
described later. Dusting for fingerprints is usually done fairly late on as
the dust gets everywhere.
Verbal evidence is also taken, such as from witnesses.
Physical evidence that may be found include: arson traces, biological
traces (semen, saliva etc), blood, clothing, documents, signs of drug use,
powder - eg from a gun, fibers, fingerprints, firearms, footwear and
footprints, glass, gloves, hair, paint, poison, soil, tool marks, wood etc etc
- Examining the body
Nobody is supposed to move the body (other than look for ID and some
superficial moving) until the coroner's investigator gets there. The
coroner is responsible for the body and everything that is on the body.
The police (or the FBI) are there to find out who killed this guy,
but the coroner is there to determine the cause of death. They really
don't like anybody moving the body until they have a chance to look at it.
Sometimes the position gives them a clue as to the cause and method of death.
Also they need to see if the lividity (where the blood has settled in the
body, it will always go to the lowest point and starts about 6 hours after
death, and is a pinkish,purplish color) matches the position of the body. It
can also help determine time of death.
Sometimes you can get away with handling the body before the coroner
arrives but you have to have a good reason. Some forensic techniques need to
be done quickly.
Before the body is moved, paper bags are put over its hands to protect
fingerprints, things caught under the nails etc.
Of course, if the "body" is alive it complicates matters. Paramedics are
called and they take the body away, leaving no body at the scene. Paramedics
tend to cut through the bullet holes in the clothing and leave medical
supplies around where they can be mistaken for real evidence. A forensic
investigator will usually go to the hospital and try to recover what evidence
they can. If the victim dies in the hospital the body will be photographed and
examined. (All hospitals have a morgue facility on premises for patients who
Just as no-one should touch the body until the coroner arrives, the coroner
can't remove the body until the forensics people have collected all the
evidence they need. This can sometimes take hours.
When the body can be removed, it is taken to the morgue. The people that
come and collect the body and take it to the morgue are called a removal
service and do not work for the coroner's office.
- Who is allowed at the scene?
Very few people. Unlike on television, there are no extraneous officers
wondering around, using the phone, going in the kitchen etc. Even if someone
at the scene is wanted urgently, no-one is allowed in to get them. Instead
they will be called to come out.
Usually the only people at the scene are the lab people. The detectives
take a quick look at the scene at the start, but then leave to follow their
own lines of enquiry. They learn about what was discovered at the scene by
reading the reports of the lab people.
- Who is in charge?
A detective is in charge of a police investigation. If the case is
high-profile, higher ranking officers may attend the scene, and then they are
technically in charge, but it still remains the detective's investigation.
Usually, higher ranks do not attend crime scenes, especially late night ones.
The one exception is if the case involves an officer in a shooting. Then,
everyone is there.
However, although the detective (or, in the FBI, a Special Agent) is in
charge of the investigation, they are not in charge of the crime scene. The
forensic people have to know everything that happens in the scene and are
allowed to dictate what can and can not be done.
- Is special clothing worn?
No-one wears special clothing. There are so many other contaminants around,
the investigators' clothing wouldn't add that much.
Only on drug lab scenes is protective clothing worn by everyone who enters
the scene. Especially with PCP labs, so much can be in the air floating
around. However, this is to protect personnel, not to protect the crime
Gloves are worn at all times in the crime scene. They don't have to be
changed everytime you touch something different, but are usually changed
- Handling evidence
It is essential that all evidence is fully documented at all stages of its
life. This is called the Chain of Custody. Whenever anyone handles the
evidence, whether at the scene, in the lab etc, they must document it. If
there is any time unaccounted for the evidence is inadmissable in court.
In "Grotesque" Scully looks at the bag that held a knife. We can clearly
see the form on the side for people to fill in if they handle the evidence.
When Mulder (and Patterson) took the knife it was a major offense as it would
make the knife inadmissable evidence.
- Crime scene don'ts
(These are taken from a brief online manual. How many of these do Mulder
and Scully break?)
Unnecessary walking about
Moving or disturbing the bodies of victims
Touching items or surfaces likely to yield prints
Allowing items to be removed from the crime scene without permission from
the chief investigator
Using toilet facilities
Washing or using towels at scene
Using telephone (unless already processed)
Allowing entry of unauthorized personnel
Commenting to news media or public
Forensic Personnel at the Scene
The number of people doing forensic work at a crime scene will vary according
to the location and severity of the crime.
- Uniformed police officers
In rural areas, sworn personnel (Cops) in uniform do a lot of the basic
stuff, like simple dusting for latent fingerprints, taking a blood sample,
taking the photographs, picking up some obvious evidence. However, this is all
they would do - just the simple stuff.
If it was a major case like homicide, they would call a forensic team from
a larger agency nearby to handle it.
Even in minor cases, they would not have the facilities to analyse the
information. They would package everything up from all other cases and send it
either to their county lab or to the FBI.
- Identification Units
Middle-sized cities have their own Identification Unit who responds to
crime scenes and who usually are people who are experts in fingerprints and
photography. They are called all sorts of names, from crime scene analysts,
fingerprint experts, crime scene investigator etc. These people will know a lot
about crime scene forensic investigation, but are not criminalists.
Criminalists would do the actual blood analysis. These people will be
sometimes in civilian clothes, sometimes in uniform. Depending on the severity
of the crime, there will be one or two people doing all these functions.
Police officers, in this case, will not be helping them (unless
asked something like "please hold this tape here!"), so you won't see
uniformed and civilian clothed people fooling around doing things.
- Large Agencies
Large agencies ie LAPD, FBI, LASO etc. have very specialized forensic
personnel, resulting in a lot of people at a crime scene all doing what in
smaller agencies would be done by one person. For example, one expert would
just do fingerprint work, at crime scenes and in the office, and nothing else.
Other experts would handle the photography, trace evidence collection, crime
scene analysis etc.
So if a crime happened and LAPD or the FBI was handling it, you would have
at the scene, in civilian clothes:
1) a fingerprint expert
2) a photographer
3) a criminalist - The criminalist would gather all evidence for serology
(blood people), physical (hairs and fibers, shoe tracks, or anything dealing
with shoes), firearms, (unless the firearms expert is present), documents
(anything having to do with handwriting analysis), toxicology (any unknown
liquids), and narcotics (any narcotics that are found at the scene would need
to be tested).
4) If one were needed, a firearms expert would be called to the scene. If a
bullet trajectory reconstruction is anticipated, the firearms people like to
view the scene.
So the detective would get all these reports from these different
departments and have to compile them and apply them to his case.
At the same time, all cities can have the county forensic lab at their
disposal, to respond to the scene or send their stuff to. Most agencies like to
do their stuff themselves, be self contained, so they try to have their own
forensic people. If you are a city or the county for that matter, you can also
send your stuff to the state lab for analysis, or even utilize the FBI lab for a
For further information, this site is a useful one for crime scene investigation. No. It is
more than useful. It is brilliant, though it has ten times more than we'd ever
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