Our Editor-in-Chief in his Editorial today (15) makes the point that damage is done to the reputation of the agency that holds back information, especially important information. In this day and age where it so easy to “leak” information and photograph it and instantly it is in the public domain, it is incredible this still happens. And the culprits are government bodies.

This time we have a memo dated 29th August containing information from a report made known only on 10th October. The report was a survey by Scenes of Crime who conducted a random sampling of staff and areas around George Town Police Station and submitted the swabs to a Jamaican laboratory for analysis.

The results showed high levels of Gun Shot Residue (GSR) on one of the cells and the hands of some officers, low levels on officers’ uniforms and other cells, and trace levels at the custody suite, the USG vehicles and police equipment.

In the memo, written to Deputy Commissioner Stephen Brougham of the Royal Cayman Islands Police Service (RCIPS) by Martin Gaule, RCIPS Scientific Support Manager, he made the claim the report could “adversely impact the value of GSR evidence found on a person suspected of firing a weapon who has been in close proximity to such areas or officers.”

Gaule recommends the following corrective actions:

1.   At the point of arrest, but only if it is deemed safe to do so, that every effort be made to avoid contact with the suspect by armed officers and if possible that the hands of the suspect be placed in paper bags or similar and secured with adhesive tape around the wrists to secure any GSR evidence.

2.  That suspects be conveyed in vehicles not normally used by armed officers and that they enter the custody suite through the rear entrance rather than the front counter area.

3.  Wherever possible suspects are sampled for GSR by trained Scenes of Crime personnel or by an officer (who does not have regular contact with firearms) under the direct guidance of or after being adequately briefed by a trained Scenes of Crime Officer.

4.   The procedure adopted for sampling of a suspect be amended to include, prior to any contact with the suspect, swabbing of the hands and gloves of the officer conducting the sampling and swabbing of the area where the sampling is about to take place i.e. table, chair etc.

5.  That officers, who use firearms either professionally or socially, be reminded of the importance of regular and thorough washing of their hands and clothes after using or being in contact with a firearm or ammunition.

6.   That the practice of random sampling of officers, equipment and areas of the police station be carried out once every six months to monitor the levels of background contamination.

The ramifications to the RCIPS could be major as Criminal Defence Lawyers can wave this report in front of the prosecution where GSR is a very important factor in the case against their suspect(s). Then there is the problem with past cases where GSR has been used to obtain a conviction.

See attached copy of the Memo (Pages 1&2)

 

GSR

Gun shot residue (GSR) is when the firing pin of a firearm strikes the primer of a cartridge the primer compound ignites sending a flame into the cartridge case.  Gunpowder in the cartridge case starts to burn, causing it to change from a solid material to a gas.  This change creates pressure within the cartridge, which in turn forces the bullet down the barrel and down range. Pressure building behind the bullet is released when the bullet exits the muzzle of the firearm.

The bullet acts like the cork in a shook up Champagne bottle.  When the bullet exits the muzzle, pressure behind it blows the gunshot residues out of the firearm’s barrel under high velocity. The residues are expelled from the barrel in a smoky cone shaped pattern.

The further gunshot residues travel from the muzzle, the broader and less concentrated the pattern becomes.  Because the various elements included in gunshot residues are very small and lack mass they lose their energy rapidly.

Gunshot residues can also be emitted from other areas of a firearm. As you can see in the above image, gunshot residue is escaping from the barrel/cylinder gap of the revolver.

The muzzle-to-garment distance can vary considerably depending on the firearm and type of ammunition being used.  Short-barreled firearms and lower velocity cartridges will not normally expel residues as far as a high velocity rifle.  At shorter distances however, they may deposit greater concentrations of gunshot residues.  Also, gunpowder can come in several forms such as ball, flake, disc, and others.  Ball powder being spherical in shape is more aerodynamic than say a particle of flake gunpowder and as a result will travel farther.  A number of other variables can influence the amount of gunshot residues that may reach a target; therefore, it is essential that the firearm and ammunition used in the shooting incident be recovered.

GSR emitted from the muzzle will travel out to distances of approximately 3 and 5 feet in most firearms but in some cases can travel even greater distances.  At the 3-5 foot range the gunshot residues may only consist of a few trace particles and make determining the firing distance difficult if not impossible.

 

As the firearm gets closer to its target the residue concentrations increase and the actual size or diameter to the pattern gets smaller.  At around 18-24 inches most firearms will start to deposit considerable concentrations of gunshot residues that may or may not be visible to the eye.

At distances of less than around 12 inches heavy concentrations of visible gunshot residues will normally be deposited.

When the muzzle of the firearm gets next to or is in contact with the target, hot gases escaping from the muzzle at high velocity will typically rip, tear, shred, and/or melt the material of the target.  A very intense deposit of gunshot residues will be found around the margins of a contact or near contact entrance hole.

There have actually been cases where a hard contact gunshot (muzzle pressed hard against the victim) caused the residues to blow through the wound tract in the victim and be deposited around the inside of the exit hole of the victim’s clothing.

GSR is normally a combination of gunpowder residues and lead residues.  I say normally because some newer ammunition is virtually lead-free.  More and more ammunition manufacturers are using lead free or low lead propellants because of the toxicity of lead.

Gunpowder residue can contain unburned gunpowder particles, partially burned gunpowder particles or the carbonaceous soot from completely burned gunpowder

From FirearmsID.com (See: http://www.firearmsid.com/a_distancegsr.htm)