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AC 1.2: Assess the usefulness of using investigative techniques in criminal investigations. Police and investigators use many different techniques to investigate crime- This AC assesses their usefulness. (strengths and weaknesses) Where are these techniques most useful (crime scene, laboratory, police station, 'street'), types of crimes (violent, e-crime, property, ect). Also link to brief where needed. Use of intelligence databases: 'Intelligence'- info that has been obtained from many sources, even confidential ones, and has been recorded and evaluated. This info can be stored on many different databases for the police to access, like: The Police National Database-contains intelligence about suspected criminal activity, as well as the data on the PNC. It holds over 3.5 billion records that can be searched for- and it itself is made up of 220 linked databases. The Police National Computer (PNC)- contains several separate databases. Stores details of over 12 million people's arrests, convictions and police cautions, with links to biometric databases for fingerprints and the National DNA Database. Vehicle registration data and info on 48 million people who have a driving licence, and on those who are disqualified. The PNC also holds info on missing and wanted persons. Crimint and the Gangs Matrix-holds info on criminals, suspects and protestors, and the Gangs Matrix holds info on suspected gang members. International databases- UK police are able...
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to access databases that share info between police forces in other countries, including: the INTERPOL databases on child sexual exploitation, biometric records (DNA and fingerprints), stolen property (like artworks), firearms and organised crime networks. Strengths Allows centralisation and sharing of intelligence across police forces, nationally and internationally- this saves time and resources as it is readily available Has become a valuable tool for making crucial links and solving crime. An example of this would be tracing offenders via DNA, which happens frequently Limitations Gangs matrix criticised as racially discriminatory, and MET police had to remove over 1,000 young black men from the database in 2011. Has been subject to leaks, like in 2017- names and addresses of 203 alleged gang members were accidentally leaked and fell into the hands of rival gangs. Some of the people named suffered serious violence. Is problematic if data is inaccurate, as false leads and even miscarriages of justice could be produced. Civil liberties issue- sometimes people only suspected of crimes are on databases. Data misuse- misuse from police officers, e.g: A USA officer used the vehicle database to locate and stalk women. Forensic techniques: 'Forensics'- refers to the scientific techniques and tests used to assist in investigating crime. There are a range of forensic experts and scientists (AC 1.1), but mostly, forensic techniques involve investigators recording evidence from a crime scene and submitting it for lab analysis. Biological material: blood, semen, skin flakes and hair. weapons DNA evidence: fingerprints and shoeprints Examples of forensic evidence fibres and threads from clothing It's essential that access to crime scenes is strictly controlled, and that investigators wear appropriate protective clothing- to avoid contaminating forensic evidence. Once evidence is collected, forensic specialists can examine it and then share the results with police in order to assist their investigation. paint flakes ● many other materials DNA analysis-area that forensics has made the greatest progress. ● DNA is found in almost every cell of the body, and apart from identical twins, everyone's DNA profile is unique. • Highly sensitive techniques for extraction and rapid analysis of small amounts of DNA samples have been developed over the years. Case study: First ever forensic use of DNA profiling This has made DNA profiling the most important development in solving serious crime since fingerprinting was invented. Scientist Alec Jeffreys developed DNA profiling in 1985. It was first used to investigate the rape and murder of 2 girls in Leicestershire in 1983 and 1986. Using the new technique, Jeffreys established that semen left in both cases came from the same man. Next, police took blood samples of all 4,583 men in the area, and found a match to Colin Pitchfork- who was convicted of both murders. The test also exonerated Robert Buckland, a 17-year-old with learning difficulties who had admitted to the 1983 killings, making him the first person to be cleared of a crime using DNA analysis. ● However, Pitchfork was only caught when a co-worker revealed to work-mates that he had taken the blood test masquerading as Pitchfork, because Pitchfork told him he had already given a sample while pretending to be a friend who wanted to avoid being harassed by police because of a previous conviction. A woman overheard this conversation and reported it to the police. The DNA analysis confirmed Pitchfork's quilt, but it was witness evidence that enabled police to catch him- The forensic evidence was not the only factor. Using relatives' DNA profiles: Even though every person's DNA profile is unique, blood relatives have similar profiles to one another and samples from family members have been used to aid the identification of perpetrators. Case study: Colette Aram was raped and murdered in 1983 by Paul Hutchinson- before DNA profiling existed. ● By 2008, police were able to develop a profile of her killer due to advances in DNA technology. Hutchinson's son had been arrested for a motoring offence, and a routine DNA sample was taken. This sample partially matched the one taken from the crime scene, so his father was arrested and convicted of the murder. Because blood relatives share similar DNA profiles, the method has also been used to identify deceased victims of homocides, suicides, and accidents. Problems with DNA evidence: Even with the several advantages of DNA analysis, there are several problems with the use of DNA evidence. Contamination of DNA evidence: If DNA is contaminated, it can lead to a miscarriage of justice, like the Adam Scott case (AC 1.1)- Where he was wrongly charged with rape in 2011 and spent 5 months in prison on remad, on the basis of a contaminated DNA sample. The danger of contamination is, if anything, greater now,since the minutest quantities of DNA can now be analysed. Problems matching samples to suspects-To get a match with DNA from a crime scene, the offender or a close relative of them must already be on the National DNA Database. However, advances in forensic technology mean it may soon be possible to identify the colour of a perpetrator's hair, eyes and skin, and their approximate age- from a DNA profile. Civil liberties: There have been civil liberties concerns about the police retaining DNA taken from people who haven't been convicted of a crime, such as those arrested but released without charge. This led to a change of law in 2012, requiring most profiles taken from people not convicted to be eventually destroyed. Cost- Until recently, DNA tests were quite expensive, but the cost of analysing a DNA sample is now around £20. Surveillance techniques: Surveillance- watching over something or someone, like using CCTV to monitor who comes and goes in and out of a building. Police use CCTV footage in criminal investigations, because it can give 24 hour coverage of a location, which provides a visual record of the crime and helps to identify the perpetrator. In major cases such as murder inquiries or the 2011 riots, CCTV images can be released to the media with appeals to the public- so they can report the identity of anyone they recognise. However, a camera is fixed, so it can't follow a target around a corner. CCTV cameras can be easy to spot, meaning criminals can avoid them or disguise themselves. The recorded images are also not always of good quality, which makes identification difficult or impossible. Covert surveillance: CCTV monitoring isn't usually pre-planned, it simply records what occurs. To compare, covert (hidden) surveillance is planned in advance and carried out in such a way that the people being monitored have no idea it is happening. Covert surveillance can come in several forms: • Attaching tracking devices to vehicles and using GPS to monitor their movements. ● Intercepting mail or tapping phones. ● Static surveillance from a fixed point, such as an unmarked, parked police vehicle, possible using binoculars or cameras. Highly trained mobile surveillance teams, on foot or in a vehicle. Covert Human Intelligence Sources: ● CHIS can also be used as they are individuals who maintain a relationship with the 'target' in order to covertly gain information. They may be undercover police officers using a false identity to infiltrate a criminal group, or informants who are criminals themselves. ● Criticisms of covert surveillance: ● There are strict rules governing covert surveillance, because it may involve unwarranted intrusions that breach the target's human rights to a private life, as well as entrapment, which is encouraging someone to commit a crime so they can be prosecuted for it. ● Overall, ethics can be a big problem (see above) Despite this, there have been a number of high profile cases, like Colin Stagg and the Justice for Stephen Lawrence campaign. Case study- Colin Stagg Colin Stagg was wrongly accused of the 'Wimbledon Common' murder of Rachel Nickell in 1992. The police used an undercover female officer in a covert operation in an effort to trick him into a confession. There have also been cases of undercover officers using the identities of dead babies to create a cover story, complete with birth records, tricking women they had targeted into sexual relationships, and infiltrating peacefull protestors. Observation: ● Police find a difference between surveillance, which is pre-planned, and observation, which is not. For example, a police officer out on patrol who unexpectedly comes across suspicious activity taking place may keep the situation under observation to decide whether a crime is being committed. Interview techniques: Interviewing witnesses or forensic and other experts can be an important part of an investigation and court case. Eye-witness testimony: EWT is the evidence given by a witness to a crime. Juries often accept EWT as an accurate account of an incident- and they give more weight to it than to other kinds of evidence. For example- the Devlin Committee in 1976 found that juries convicted in 74% of cases where line-up identification was the only prosecution evidence. However, juries' faith may be misplaced. For example- Innocence Project in the USA has found that over 70% of 352 wrongful convictions that were overturned on the basis of DNA evidence, eye-witness misidentification played a role in convicting the innocent- 15 of which spent time on death row. Memory problems of EWT: Problems with relying on EWT are mainly to do with memory. There are 3 aspects to memory: Acquisition-witnessing the crime and absorbing what is happening. Retention- Storing the information in the memory. Retrieval- recalling the memory, like when you are interviewed by the police or identifying someone in a line-up. Memory acquisition: There are many things that affect how successfully we form a memory of a crime, like: Duration- the longer we're exposed to an event, the better we remember it. ● Time of day- Kuehn found that witnesses gave the most detailed statements of events seen in full daylight or at night. (night because they paid more attention due to poorer visibility). In twilight, witnesses overestimate the viewing conditions and could recall less detail. Time distortion- Witnesses overestimate how long emotional or dramatic events, like an assault, actually last. ● Violence distraction- Witnesses recall violent events less accurately, which could be because seeing violence can make them highly anxious, which impairs memory. Weapon focus-Loftus et al found that where a weapon is involved, witnesses focus on the weapon and this stops them from forming detailed memories of the offender. Memory retention: There are 2 main factors that affect how well a witness retains memories of a crime: ● Time-memory traces in the brain fade over time and info is lost. However, there is one exception: memory for faces doesn't seem to fade over time. This means a witness can still identify an offender, even if the details of the crime aren't remembered. Discussion of the event- this could be with friends or other witnesses- this can help/aid in having a more detailed recall, but can also reduce the accuracy of the memory. Memory retrieval: Witnesses have to retrieve a memory when a police interviewer asks them to recall a crime. However, misleading info and leading questions can affect the witness's memory and make inaccuracies. - research by Loftus and Palmer shows this: They showed people a film of a car crash, and asked some of them- 'How fast were the cars going when they hit?' Others were asked the same questions, but with 'bumped' or 'smashed' instead of 'hit' at the end of the question. The 'smash' group estimated the speed at average 40mph, the 'bumped' group said 38mph, and the 'hit' at just 34mph. Loftus and Palmer later asked them a leading question- 'did you see any broken glass in the film?' 32% of the smashed gro said they had. ● Only 14% of the hit group said they had too. In fact, there was no broken glass in the film. This research suggests that witnesses' recall of a crime could be distorted by the way questions are worded in a police interview or a cross-examination in court- which makes their evidence unreliable. The cognitive interview: With these issues, it's important to ensure that police interview techniques maximise the chances of gaining accurate info from witnesses. Psychologists recommend using cognitive interviews instead of standard police interviews. These use 'cues' to encourage recall, where they use strategies like: ● Reinstating the context- asking the witness to imagine themselves back in the situation. Reporting everything they saw- no matter if the things seem irrelevant. Expert witnesses: Forensic experts can play an important role in criminal investigations (AC 1.1). Police can interview experts and specialists for info and advice on different aspects of their investigation. These interviews are often conducted after the expert has submitted a report. Police can ask questions for clarification and to develop their lines of inquiry into the crime. Experts include forensic specialists with knowledge of areas like: Experts in blood patterns, fires, explosions and gunshot residue can answer questions about a crime scene. ● Psychologists can offer an analysis of the offender's likely personality, behaviour patterns and psychological characteristics- often as part of an offender profile. Pathologists can analyse the likely cause of death in homicide cases, based on autopsies. Entomologists (insect specialists)- calculate time of death based on how developed the blowfly maggots are that are on the corpse (they lay their eggs on dead bodies). Forensic anthropologists can assist police in identifying dead victims by analysing human remains. ● ● Experts can also be questioned in court. Expert witnesses may also be asked to give an opinion based on their expert knowledge- which is different to eye-witnesses who have to give an account of what they saw. However, like in the case of Sally Clark, expert witnesses can get it wrong, which can lead to miscarriages of justice. Profiling techniques: Offender profiling- ● Based on the idea that we can predict the characteristics of an unknown offender, by examining the characteristics of their offence and victim. The same way an offender may leave physical evidence on the crime scene like fingerprints, they also leave behavioural evidence. For example- in a murder this could involve how the victim was killed and how their body was left. Advantages: profiling may: ● Link crimes committed by the same offender • Help predict future offences, which allows offenders to be caught earlier, which avoids future victims. ● Help police target their resources and prioritise suspects. There are 4 types of offender profiling: typological profiling (aka crime scene analysis), clinical profiling, geographical profiling and investigative psychology. Typological profiling (crime scene analysis): Typology- a classification system. Typological profiling aims to classify offenders into 'types' that have different characteristics based on how they behave at the crime scene. (which is why it's called crime scene analysis). If a crime scene is analysed carefully, it's possible to identify the type of offender and characteristics they may have. For example- personality, lifestyle, relationships and motives. So, the profiler gathers all the available info about the crime scene, the victim, and the forensic evidence. • Typological profiling divides crime scenes and offenders into 2 types- organised and disorganised. The table uses the example of murder cases to show the difference between the types: Type of murder Organised crime Crime is planned, such as murderer taking a weapon Attempts to control the victim Leaves few clues on crime scene (removes evidence) • Victim is a targeted stranger Disorganised crime Spontaneous- little planning/prep, such as weapon improvised at the crime scene Radom, disorganised behaviour Minimum use of constraint Little attempt to hide evidence at the crime scene, like leaving the weapon behind Likely characteristics of the murderer Organised murderer Above average intelligence, but possible an underachiever Manipulative, cunning, outwardly normal where sadistic personality is concealed ● Socially and sexually competent ● ● Usually living with a partner ● ● Angry/depressed at time of attack Follows media coverage of attack Disorganised murderer Lives alone and near to the crime scene Sexually and socailly inadequate Suffers severe forms of mental illness • Physically or sexually abused in childhood ● Frightened/confused at time of attack ● Profiles then can be used by police to identify likely suspects and narrow down their search. Can also be used to predict likely future behaviour of offenders, like whether or where they'll strike next. Typological profiling was originally developed by the FBI in the 1970s, USA. Now, more typologies have been made to classify rapists, based on their behaviour when offending. For example- the 'power assertive' type uses rape to assert his masculinity, and 'power reassurance' type is motivated by fear of sexual inadequacy. Other types of rapists are 'anger-retaliatory' and 'anger-excitement'. Evaluation/limitations: criticisms from David Canter Info available at crime scenes can be quite limited and not collected under strict conditions. Speculations about the offender's likely personality, relationships and motives aren't much help to the police in finding them. Profile is based on the profiler's subjective opinion about which evidence is important- means different profilers can make completely different profiles- about the same case The typology is based on interviews that the FBI conducted with just 36 convicted serial killers and rapists. This is a very small sample, and the offenders may be untypical of those who aren't caught- as well as being manipulative and dishonest. However, typological profiling has helped solve some high-profile crimes in several countries. It can also help police predict the likelihood of future crimes. Clinical profiling: This type of profiler is usually a psychiatrist or clinical psychologist. ● They use their professional knowledge and experience to get in the mind of the offender. The aim is to gain insights about the offender, which allows them to predict their behaviour. Instead of using typologies to classify crimes into general 'types'- they see every case as unique and individual. Best known clinical profiler in the UK is Paul Britton, who immerses himself in the evidence to produce intuitive insights into the offender's thoughts and feelings when committing a crime. The TV series 'Cracker' is said to be modelled around Britton. Evaluation/criticisms: As clinical profiling is based on the profiler's clinical experience in working with convicted offenders- it may be untypical or limited. It can produce unsupported speculations about the offender's characteristics and motivations. This sidetracks an investigation, and can even lead to the arrest or conviction of innocent people. This allows the offender to be free and commit further crimes- the case of Rachel Nickells shows this. Case study- Clinical profiling: Profiler, suspect and murder of Rachel Nickell ● Nickell was murdered in broad daylight on Wimbledon Common, July 1992. The police were convinced Colin Stagg was the murderer, but went to profiler Paul Britton for help as they had a lack of froensic/other evidence. Journalist Matthew Weaver says that Britton made a plan to tempt Stagg into a confession. ● ● This involved a 'honey trap'- where an undercover police officer called 'Lizzie James' faked romantic interest in the suspect and had the same interest in Satanism as him. Despite these efforts, he didn't confess. Nevertheless, Stagg was charged with the murder in August 1993. But when the case went to court the following year, the trial collapsed. The judge condemned the honey trap as 'a blatant attempt to incriminate a suspect by positive and deceptive conduct of the grossest kind', and mentioned the abusive and unethical way psychology had been used. Stagg was given £706,000 in compensation. Meanwhile, Samanthat Bisset and her 4 year old daughter were murdered in their south-east London home in November 1993. In October 1995, another man called Robert Napper was convicted of the murders. When Nickell's case was reopened in 2008, Napper was convicted of this murder also. Britton had been a consultant inn both murder cases, but journalist Richard Edwards says at the time, Britton ruled out any link between the cases. If Napper was charged with the earlier murder, he wouldn't have been free to kill again. Geographical profiling: There are crimes in some locations more than others, which is because offenders make choices about where to offend. This choice is usually based on what they do in their non-criminal behaviour in everyday life, E.g.: they may see a crime opportunity on the way to work and return to it later. This is the idea that geographical profiling is based on. It aims to work back from where offences happen, to try and find where the offender lives, which is based on 2 main principles: ● The least effort principle- Given 2 identically attractive targets. The offender will choose the one nearer to home. The buffer zone principle- Although offenders won't travel unnecessarily, they'll avoid offending too close to home for fear of being recognised. This is their buffer zone. Canter and Gregory apply the principles to see these 2 patterns of offending: The marauder-Has a home range and travels within the vicinity, moving out from home in a different direction each time so they don't come back to the area of their most recent offence. Therefore, if we draw a circle through the location of the two offences that are furthest apart, we can expect the offender's home to be somewhere in the centre of the circle- Canter calls this the circle theory. The commuter- travels away from their home area to offend in another. Once there, locations of the offences tend to cluster together. If they cluster around a main road or station, for example, we might think the offender is using this route to reach victims, therefore meaning the police can use this info to focus their search. Evaluation of geographical profiling: The method has had some success in predicting where to find offenders in a range of crimes, such as rape, arson, and burglary. However, profilers have to be sure that all the crimes were definitely committed by the same person. This can be hard if the offender's mode of offending begins to change as they commit more crimes. The marauder/commuter model assumes offenders always follow one pattern or the other, but some switch between the 2. Profilers have to be sure that they haven't missed any crimes outside of the circle. Otherwise, the point they've labelled the centre will be in the wrong place. Geographical profiling relies on accurate data. If crime locations aren't recorded correctly, this will make the map inaccurate. Investigative psychology: This is mostly associated with Canter, and includes ideas from geographical profiling, like offenders being likely to offend in areas they know well. However, other features are also included. The offender consistency principle- ● This is the central idea of investigative psychology, which says that an offender's behaviour is consistent between their offending and non-offending behaviour. Therefore, the way they commit their crimes will reflect their everyday behaviour and personality traits. ● For example- a rapist who uses degrading language towards victims may indicate a man who regards women as objects and who has difficult or failed relationships with women at work or at home. Criminal narrative themes- • Investigative psychology also uses the idea that criminals base their offending on 'criminal narrative themes' or personal life stories that give their crimes meanings. The offender may see themselves as: 'elated hero', 'depressed victim', 'calm professional', or 'distressed revenger'. ● For example- the elated hero sees his crime as the brave and manly thing to do, an enjoyable, exciting adventure. To compare, the depressed victim believes that events in his life are beyond his control and that he has no other choice but to commit his offence. While doing so he feels confused, depressed, and lonely. Evaluation of investigative psychology: Uses concepts that can be tested in practice, like the offender consistency principle. Uses both large scale data on patterns of offending and narrative themes to understand offender's motives. Has been proved successful in cases covering a range of different crimes. However, it relies on the quality of data on offences and offenders, meaning predictions using inaccurate data will be inaccurate. (same criticism as geographical profiling).