Identifying and Collecting Physical Evidence

January 8, 2018 | Author: Anonymous | Category: Social Science, Law, Forensic Science
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Law 120



To prove beyond a reasonable doubt that the accused was present at the crime scene when the offence was committed, the collection, preservation and analysis of physical evidence is a crucial aspect of police work.



Physical evidence – any object, impression or body element that can be used to prove or disprove facts relating to an offence. This type of evidence carries greater weight in court over witness statements.



Forensic evidence – application of biochemical and other scientific techniques to criminal investigation.



Forensic scientists examine/analyze physical evidence found at a crime scene. They do most of their work in labs but also spent a lot of time giving expert testimony at trials and inquests. Some specialize in autopsies or firearms. Others can determine a car driven by an accused by the paint chip left at the scene.



The most frequently used tools in the commission of crime are hammers, screwdrivers, and crowbars. Often these tools will have individual characteristics on their surfaces or edges that can be detected in crime laboratories. These marks can be made either in the manufacturing of the toll or by normal wear and tear.

Impressions are patterns or marks found on various surfaces, caused by different objects such as fingers, gloves, shoes, tires or tools. Collecting impression evidence is done in two stages. First, the impression is recorded by photographing or scanning it, or taking a mould. Then the police try to match the impression with the object that made it, such as matching a fingerprint lifted at the scene with a print taken from a suspect.  Impressions have two characteristics: 1. class characteristics – general attributes of an object such as type, make, model, style and size. i.e. tires 2. individual characteristics – specific and unique features of an object. i.e. specific wear and tear on a particular tire on a particular car. 

A fingerprint is a patterned mark left on a surface by a fingertip. Prints can also be taken of a person’s hands, feet, or toes, but fingerprints are easier to work with and classify. Because fingerprint patterns never change and are unique to each individual, a fingerprint is the best type of impression to use to identify an offender. No two people have been ever found to have the same exact fingerprint. Even identical twins have different patters.  There are two types of prints. A visible print can be observed by the naked eye and is usually formed when the fingerprint is coated in dirt, blood, grease or some other substance. This type of print can be photographed immediately. A latent print, made by the perspiration and oils that naturally form on the skin surface, cannot be seen by the naked eye. This print has to be ‘developed’ to be photographed. Three methods are used to develop latent prints. 

prints on non-absorbent surfaces, such as metal and plastic, can be dusted by using a graphite power that sticks to the ridges of the print. The print is then lifted using adhesive tape and placed on a white cardboard surface where it can be photographed. The officer who lifted the print initials the cardboard and it is stored for use later in court.  The technique called ‘iodine fuming’ is used to lift prints from absorbent surfaces such as paper and cloth. The area being investigated is placed under iodine fumes; any existing fingerprints absorb the iodine and become visible.  A laser beam can be used to illuminate the print. Sweat compounds deposited on the surface absorb the laser, and the print turns yellow and can be photographed. 



Gloves do not necessarily hide a criminal’s fingerprints anymore. Police can use glove impressions to identify a suspect in almost the same way they use fingerprints. To make a positive identification, they compare the impression’s class characteristics with the gloves of a suspect.



If the police can find four shoe prints – two right and two left – they can learn a lot about a suspect. These prints can help them determine the suspect’s approximate height and weight, any injuries he/she might have sustained committing the crime, whether the suspect was carrying anything and whether he/she was walking or running. Tire impressions can help investigators determine the type of tires, make of car, and direction it was traveling when it entered or left the crime scene.



The police may issue an appearance notice for summary conviction offences, hybrid offences, and less serious indictable offences. This document names the offence with which the accused has been charged. It also gives the time and place of the court appearance. The officer must believe that the accused will appear in court on the given date. The accused must also sign the document and receive a copy of the notice. The officer will then swear an information before a judge or justice of the peace. This document states that the officer believes on reasonable grounds that the person named in the appearance notice committed an offence.



For more serious indictable offences, the police will arrest the suspect and take the suspect into custody. Arresting officers must:    



identify themselves advise the accused that he or she is under arrest inform the accused of the right to a lawyer inform the accused of the charges

The purpose of the arrest is to lay charges, preserve evidence and prevent the accused from committing further offences. Any officer can arrest without a warrant if there are reasonable grounds to believe that someone committed an indictable offence, is committing an indictable offence or summary offence, or is about to commit an indictable offence. After the arrest the officer must swear an information before a judge or justice of the peace.



If the accused resists arrest, the police can use as much force as is necessary to prevent an escape. The police are criminally liable for the use of unnecessary force. In certain circumstances, they can apply force that could cause death or serious injury if it protects other from death or bodily harm. In 1994, Parliament passed a law that gave the police and anyone assisting them the power to use deadly force. They can do so in the following situations:  the behaviour of a suspect might cause serious harm or death to

others.  the suspect flees to escape arrest  there is no alternative means to prevent escape



When an officer stops someone for questioning, that person is being detained. People who are detained do not actually have to answer questions unless they are in a specific situation, such as a police spot check on a busy highway or being placed under arrest. Detention should lead quickly to arrest—otherwise, the person should be free to go. If a police officer insists on questioning or searching a reluctant individual, that person should immediately demand to see a lawyer and write down the badge number of the officer and the names of any witnesses. Citizens detained illegally may sue the police for false arrest or detention or complain to the police commission. A citizen is allowed to use as much for as necessary to resist and illegal arrest or search. However, the force used must be reasonable.



Someone charged with committing a crime has the right to be informed promptly of the reason for arrest and the right to obtain a lawyer without delay. The Supreme Court of Canada has ruled that this includes being advised of the availability of a duty counsel (a lawyer on duty at the court). The police must also inform the accused that legal aid is available if that person cannot afford a lawyer. A request to contact a lawyer must be honoured immediately. Anyone who has decided to hire a lawyer can refuse to answer any further questions, except those necessary to complete the charge, such as name, address, occupation and date of birth.



When people are read their rights, they must truly understand them. If the accused is intoxicated, the police must wait until they sober. If the accused cannot understand English or French, they must be read their rights through an interpreter. Once they decide to contact a lawyer, they must have access to a phone and must be allowed to talk privately to their lawyer. They have the right to give up counsel and answer police questions.



Police officers are responsible for their conduct and behaviour when carrying out their duties. If they break the rules of police conduct, they can be charged under criminal law or sued under civil law. Each province has a board that reviews complaints from citizens concerning police conduct. Police officers often have to make quick decisions to save their own lives and those of others. At all times, officers must act on reasonable grounds using as much force as is necessary for that purpose.



The accused does not have to take part in a line-up, where several individuals, including the suspect, line up for possible identification by the victims or witnesses. Nor must the suspect take a polygraph test (lie detector test) or give blood, urine, or breath samples (except in cases of impaired driving offences). The police are allowed to obtain DNA samples from a suspect but they must have a warrant to do so. It actually might be to the suspect’s advantage to permit evidence to be collected. For example, when murder has been committed under the influence of drugs or alcohol, the extent of the influence might affect the outcome of the trial or even the sentence.



If the accused flees the scene of the crime, police can swear an information before a judge/justice of the peace. A document called a summons orders the accused to appear in court at a certain time and place. It is delivered to the accused by a sheriff or a deputy. If the police can show a judge that the accused will not appear in court voluntarily, the judge will issue a warrant for arrest. It names/describes the accused, lists the offence(s), and orders the arrest of the accused. There must be reasonable grounds to believe that the accused committed the offence. Otherwise the judge will refuse to issue either the summons or warrant.



Citizens can make arrests under certain circumstances. This law gives store detectives, private detectives, and other citizens the authority to make arrests. The Criminal Code says that any one may arrest a person who is committing an indictable offence or who, on reasonable grounds, believes has committed an indictable offence and is escaping from or freshly pursued by lawful authority. The owner of a property or an authorized person by the owner may arrest anyone without a warrant who is committing a criminal offence on or in relation to that property.



Informed and responsible citizens may want to cooperate with the police. Innocent persons often show their innocence by immediately giving information to the police. This can save time and money. Despite the presumption of innocence, the police tend to form conclusions based on an individual’s behaviour when being questioned.



Once a person has been arrested, fingerprinted and photographed, the police will often release the accused until the trial. Release is usually automatic for people accused of a summary conviction or indictable offence that carries a fine of $5000 or less. If the police believe the accused will appear in court voluntarily and will not commit and offences while awaiting trial, the accused will sign a promise to appear. If the accused does not appear on the assigned date, the court will usually issue a bench warrant for his/her arrest.



In some cases, the accused may be required to sign a recognizance – a guarantee to appear in court when required. A fine of up to $500 may be levied if the accused fails to appear. Unless the accused comes from another province or lives more than 200km away, a deposit is not usually required. The police may also request a surety, someone who is willing to pay a certain sum of money if the accused fails to appear at trial. The surety also has to sign the recognizance form.



Usually the police will try to keep suspects accused of serious indictable offences in custody after arrest. In such cases, the accused has the right to make a bail application. Bail is the temporary release of a prisoner who posts a sum of money or other security to guarantee his/her appearances in court. A bail hearing must be held within 24 hours of an arrest, or if a magistrate is unavailable, as soon as possible thereafter.



Section 11 of the Charter guarantees no one is to be denied reasonable bail without cause. If the Crown does not want the accused released before trial, a show-cause hearing is held to ‘show cause’ and convince the judge that the prisoner should stay in jail until the trial date. “Cause” includes reason to suspect the accused may flee; concern that releasing the accused may be a threat to the safety and protection of the public, or any other just cause. If the Crown is successful, the judge will issue a detention order to keep the accused in jail.



   



Some circumstances may justify a reverse onus, which means that the burden of proofs shifts; rather than the Crown having to show cause that the accused should be imprisoned, it is up to the defense to show cause why bail should be granted. This happens when: The accused is charged with committing an indictable offence while already out on bail offence is indictable and the accused is not a Canadian citizen The charge involves failure to appear or breach of a bail condition The accused is charged with importing, trafficking, or possession for the purpose of trafficking narcotics (or conspiracy to commit any of these crimes). If the accused falls into one of these categories, bail will be denied unless the accused convinces the judge that he/she will attend court as required, not commit a crime while out on bail, and not interfere with the administration of justice in any way.



If an accused person who has been arrested and denied bail believes that he or she has been illegally detained, that person can file a writ of habeas corpus to appeal the court’s refusal to a higher court.



A writ of habeas corpus requires the Crown to produce the detained person in court and then give reasons to justify keeping this person in custody after trial. It also requires the Crown to show that the prisoner is not being mistreated in any way. If the Crown cannot justify the continued detention of the prisoner to the higher court’s satisfaction, the court may order the prisoner to be released until trial.

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