Transcript Firearm Injuries

Firearm Injuries
Medico Legal Module
21st Batch
June 2014
Dr. Sanjaya Hulathduwa
MBBS, MD, DLM, DMJ Path(Lond)
DMJ Clin(Lond) , Dip. Crim, MFFLM(UK)
Senior Lecturer
Firearms
Firearm - a device designed to propel a
projectile through a cylinder/ barrel.
The force needed for the propulsion of the
projectile is usually generated by the
pressurized gas produced by the
combustion of a small amount of explosive
material known as propellant in an enclosed
space.
Ammunition
It is a general term to denote cartridges,
grenades, mines, rockets and artillery.
Cartridge
‘complete round used for firing after insertion in
to a barrel ‘.
Smooth bore weapon cartridge is usually
consisted of a case with a metal base, propellant,
projectile (shot), cap/primer and wads. The shot
usually consists of multiple metal balls.
Rifled bore weapon cartridge is made of metal
alone. The two main components of the cartridge
are the bullet (the projectile) and the case.
The rifled bore weapon cartridge has a length
(height) and a caliber/ bore.
Firearms can broadly be divided in to two
main types.
1. Smooth bore weapons
2. Rifled bore weapons
Smooth Bore Weapons
Types of Smooth Bore Weapons seen in Sri Lanka
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2.
3.
4.
Breech loading shot gun
Breech loading shot pistol
Muzzle loading shot gun
Muzzle loading trap gun (‘Kandan
thuwakkuwa’, ‘maruwela’, bandina
thuwakkakuwa’) – A country
made shot gun
5.
6.
Muzzle loading shot pistols
Swan-off shot gun (‘Galkatas’) – An improvised
modification of shot gun
A shot gun could be a muzzle loader or a breech loader.
Muzzle loader
Ammunitions do not come in a compact form.
Components of a shot should be refilled before each
shot
Breech loader
Ammunition is always a standard factory made (shot
gun cartridge).
A shot gun is of two types
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Single barreled
Double barreled
When double barreled, they are usually
positioned side by side or rarely one below the
other.
Rifled weapons
A rifled weapon has a barrel with multiple fine
grooves which make the bullet to spin around its
own axis when it leaves.
This gyroscopic movement will minimize the
wobbling of the bullet enabling it to keep its track
to find the target thus enhances the accuracy.
Types of Rifled bore weapons
1. Revolvers
2. Self – loading pistols (semi automatics)
3. Sub machine guns
4. Machine guns
5. Self – loading rifles (SLR)
6. Snipers
Identification of Firearm Injuries
A firearm injury is usually a perforating laceration.
The identification of an injury as a firearm injury is based on
the following criteria;
a. Familiarity
b. There is an entry, track and an exit.
c. The characteristic features of a firearm injury - abrasion
collar, burning, blackening and tattooing may be
present.
d. The history by eye witness – circumstantial evidence
Effects and Components of Firing
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A bullet or a collection of pellets (shot)
Wads (if available)
Residue of primer (burnt, partially burnt and unburnt)
Residue of propellant (burnt, partially burnt and
unburnt)
Residue lubricants
Fowling present in the barrel due to previous shot
Compressed gas containing soot
Flame
Heat
Noise
Medico-Legal Issues in the Investigation of
an Alleged Firearm Death
•Is it a firearm injury or not?
•If it is a fire arm injury, what is the nature of the firearm
and ammunition?
•How many fire arms have been used?
•How many shots have been fired?
•What is the sequence and direction of firing?
•What are the circumstances? Are they accidental,
suicidal, homicidal or done in self defense?
•Recovery of spent cartridges and other trace
material from the scene.
•Have the spent cartridges been shot from this
specific gun? (Specific identity of the weapon)
•Identity of the assailant.
•Identity of the deceased.
•Identity of the entry, the path inside the body and
respective exit wounds.
•The cause of death
•Time since death
•Possibility of volitional activity.
•Reconstruction of the event.
•Approximate distance of firing.
Entry Wounds and Exit Wounds
Entry Wounds
•Usually smaller, circular or oval (approximately the size of
the missile)
•Abrasion collar and contusion collar are present.
•Burning, blackening and tattooing may be present.
•Muzzle mark may be present.
•Margins are inverted.
•Clothes are driven inward in the track.
•Pinkish discolouration of the wound may be present due
to Carbon monoxide.
•Beveling of the inner table of the skull.
Exit Wounds
•Typically large and irregular. (but could be smaller. Ex: in
contact and near contact entries)
•Abrasion collar absent.
•Burning, blackening and tattooing absent.
•No muzzle mark.
•Margins everted.
•Tissues from the track protruding out.
•No carbon monoxide.
•Beveling of the outer table of the skull.
Range of Fire
Smooth Bore Weapons
Contact range – Muzzle mark on the skin around the entry wound. Burning,
blackening and tattooing with pink discolouration (cherry pink colour due to CO).
Near contact – No muzzle mark but with evidence of local explosive effect and
burning, blackening and tattooing.
Within 1 foot – single entry with burning, blackening and tattooing.
Within 2 feet – single entry with blackening and tattooing only.
Within 3 feet (1 yard) – single entry with tattooing only.
Beyond 3 feet – tattooing is absent and the dispersion of the pellets begin and
there will be individual entries caused by the dispersing pellets either singly or in
combination.
Rifled Weapons
Contact range - Muzzle mark on the skin around the entry wound. Burning,
blackening and tattooing with pink discolouration.
Near contact – No muzzle mark but with evidence of local explosive effect and
burning, blackening and tattooing.
Within 6 to 12 inches - Burning, blackening and tattooing.
12 to 18 inches – Blackening and tattooing only.
18 to 24 inches – Tattooing only.
Beyond 24 inches – Tattooing absent.
Extreme ranges – The entry is large and ragged.
Direction of Fire
The direction of fire can be determined by the following factors.
The shape of abrasion collar, contusion collar, burning, blackening
and tattooing;
Circular –fired at right angle
Elliptical – fired at an angle
The beveling of the skull;
Equal on all sides – fired at right angle
More on one side – fired at an angle
Shelving and undercutting are seen when fired at an angle.
Circumstances of Fire
•Homicidal
•Suicidal
•Accidental
Suicide
Homicide
Usually single injury (may be multiple) with Multiple injuries on various parts of the
one fatal injury.
body with more than one fatal injury.
Weapon found close to the body usually Weapons not found with the body or the
gripped in hand in cadaveric spasm.
surroundings.
Entry wounds are found in accessible sites.
Entry wounds can be at any place of the
body.
Entry wound in an elective site such as Not an elective site.
temple, mid forehead, roof of mouth, under
the chin, precordium.
Range always contact or near contact unless Range beyond arms reach (distant range)
a mechanism is used to pull the trigger.
Associated with psychiatric disturbances Associated with enmity, robbery, rivalry etc.
and previous para- suicidal attempts.
Usually no eye witnesses.
Eye witnesses’ accounts
Medico legal investigation
•History – reference to type of gun, number of shots, range and
relative positions of victim and assailant.
•Visit to the scene
•Identification of the body
•Preliminary procedures
Photography
X – rays
•Collection of trace materials
(missiles and wads, soot, burnt and unburnt gunpowder from the
clothing and the entry wounds, gun powder from the hands of the
weapon-user -useful in suicidal firearm injuries)
•Clothing – for burns, powder residues and infrared photography
•General external examination
•Specific external examination – entry and exit wounds
•Internal examination (track including injuries to internal organs
and tissues/ recovery of pellets, bullets wads etc.)
•Laboratory investigations by the Forensic Ballistics expert
•Documentation and reporting