The use of forensic evidence by both the prosecution and the defence
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DNA profiling evidence can be used by both the prosecution and the defence, as can all types of forensic evidence. However for the evidence to be used and examined, it has to be requested by the prosecution or the defence. The evidence does not automatically appear in the forensic laboratories ready for examination. It is the police who usually ask for the assistance of the forensic science experts, although it may sometimes be the Crown Prosecution Service who does this. Forensic evidence is usually used by the prosecution more than it is used by the defence for this simple reason. In an investigation, it is the police who get to the scene of a crime first, and using the evidence they find there, they have to endeavour to catch the perpetrator. To be able to do this, they have to understand the evidence they have been presented with, and this understanding can only be obtained by the use of consulting expert knowledge. In court, it is the prosecution who presents their case first. In the whole of the court proceedings, the prosecution goes first. It is the first to have the evidence, and therefore the opportunity to examine it, and gain its value to their case. Only after the prosecution has finished with it do they tell the defence of its existence so that they can try to use it to their advantage.
The majority of cases that go through the criminal courts find no need for the use of forensic science evidence. But more serious crimes are more likely to require the use of forensic evidence. Even then it is argued by some that the police use forensic science as a last resort when they finally concede that the defendant is not going to plead guilty. Many people believe that the prosecution should use forensic science evidence more readily, as it can show or even prove a vast amount of things. However, it is generally only in the more serious cases, such as murder, rape, assault, and less often, burglary, that forensic science evidence is put to use by the prosecution. Forensic science can only be collected at an early stage, and the likelihood that it may be sought diminishes as time passes. When the defence finally becomes involved in the process, often there is little new evidence left for them to work with, and the old evidence that the prosecution worked on may well have perished beyond redemption through the tests done on them. All the defence can do is to check the reliability of the work that the prosecution has done.
The process by which the prosecution can use the forensic evidence is easier than that for the defence, as the police have control of the evidence throughout the whole proceedings. In fact, it is sometimes the case that the police hold up the proceedings, as they keep the evidence, preventing the defence form examining it. The police and prosecution are under no legal duty to preserve possible evidence, or invite the defence to the scene of the crime or the investigation as a whole.
Another reason that evidence is more easily used by the prosecution is that the FSS (Forensic Science Service) has until recently done mostly prosecution work, and is closely connected to the police. When the police want some evidence examined, they merely have to contact the FSS. The defence however, wary that the FSS seem to lean towards the prosecution, find it more difficult to find sufficient experts that are independent of the FSS.
As can be seen above, the prosecution is the side that uses forensic evidence most frequently. This may be the reason why so many people think that forensic science is used only to establish the defendant�s guilt. However, this is not true. It is also used successfully by the defence, although not so often. For example, if the prosecution encounters forensic evidence that does not uphold their case, and may exculpate the accused in some way, they may not present this evidence in court. However, they must give all their findings to the defence before the case goes to court, so that they may use them. The defence may then do the same tests, or different tests if necessary, to be able to obtain the evidence that the prosecution found. They may then use this to help show that the accused is not guilty.
In the same way, the defence, when doing their own forensic examinations may find that their evidence differs from that of the prosecution. If it differs in a way that is helpful to the case of the defence, this may be brought up as evidence. It may also still show that the defendant is guilty, but the prosecution results are faulty. If this is the case, the defence is likely to be able to use this evidence to show that the prosecution expert has not been as careful in forensic processes as he could have been. If this can be proved in court, the evidence may be deemed to be inadmissible.
The problems posed to the defence, as I have already mentioned are various. FSS laboratories, although no longer officially police orientated, are still viewed by many defence counsels as being so. The alternatives are expensive and it is difficult to find a completely independent scientist who is willing to examine the evidence on the behalf of the defence, and who has the expertise in the right field.
3.3 Benefits of forensic evidence in court
So far I have discussed how forensic science evidence fares in the investigation before it is used in court - it has its strengths and its weaknesses. This is the same when this evidence reaches court. Although sometimes it can be very useful, there is a lot of controversy surrounding its use.
Forensic evidence can show only two things but in a variety of ways. It can prove that the accused is guilty, or it can prove that the accused is innocent of the crime for which he is on trial. In this way, forensic science is exceedingly valuable. An example of how useful such evidence can be can be seen in the case of the murder of Paul Kingsley by Anthony Sinclair. In this case, the victim, a nine year old boy named Paul Kingsley, never turned up to Scouts one evening, nor did he return home that night. His body was found soon after having been violated and strangled. Evidence was scarce, and the case was investigated for a long time. It was noted that some fibres that were found on the clothes of the boy did not belong to him or any of the clothes in his wardrobe. They were analysed and it was discovered that they originated from a factory in Switzerland. The only people that used that type of carpet fibre in that particular shade in Britain were a commercial company. But it was discovered, after a long period of detective work that an off-cut had been used to carpet Anthony Sinclair�s car. In conjunction with other circumstantial evidence, this forensic evidence led directly to the arrest of the accused, and finally to his conviction. This case is a perfect example of how painstaking forensic work can be so useful to the court.
There are admittedly less of them, but there are a substantial amount of cases that also use forensic science evidence successfully to prove that the accused did not commit the crime. It may also prove that the accused is not guilty of murder, but instead of manslaughter. An example of this is the death of Barry Stone. The police were convinced that Patrick Miller�s version of events - that Stone fell when they were fighting, hit his head and died, was just a story to hide the fact that Miller killed him. They thought that his death was premeditated, as there was a lack of entomological evidence at the burial site that should have been present if Miller was telling the truth. The pathological expert however could show through forensic evidence that the story being told was correct. Stone�s only serious injury was to the back of his skull. This sort of injury is consistent to Stone falling over and hitting his head. Despite this evidence, Miller was charged with murder, but was found guilty of manslaughter instead.
Forensic science was also a main factor in convicting Gordon Hay and exonerating an earlier suspect. In 1967, Linda Peacock was beaten and strangled. On her body was a bite mark. The detectives in charge of the case had 29 men from a local detention centre as suspects, and they were all asked to provide a set of impressions from their teeth. Having studied these impressions, everyone involved, including Home Office pathologist Keith Simpson, believed that the killer was most likely the 14th suspect. However, the evidence was not good enough, and more was needed. When a suitable female body was available, teeth impressions hinged in the correct fashion were used to test bite marks on the woman�s body. These showed beyond reasonable doubt that the attacker was not the 14th suspect at all. Further testing showed that in fact the bite marks originated from the mouth of suspect number 11 - Gordon Hay.
There are many other ways in which forensic evidence can be useful to show innocence as well as guilt. In recent years, there have been many successful appeal cases, based on forensic evidence - not because of what it shows however, but because of errors in its interpretation. One of the more famous of these is the appeal of the Birmingham Six, where it emerged that there could be innocent contamination of the convicting chemical from a range of everyday things. After this appeal investigations into forensic evidence took place.
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