Murder is defined as ‘The unlawful killing of another human being under the queen’s peace with malice forethought  . This definition provides an understanding of what the law states of murder; and furthermore shows that a person needs to have intention of committing murder. But the issue that constitutes is what makes a murderer to commit violent and unlawful acts.
A criminologist would state that the background of the murderers comprise in a murder killing, but there is mainly a combination of factors that help perform these unlawful acts and they are biological, psychological, social, and economic. A criminologist would state that a lower class group or an lower class individual at the age of 16 – 20 tend to commit murders outstanding to the monetary or the social backgrounds and society they perpetrate in but issues are taken into account for mandate is the background reasons that build up unlawful acts of a murderer are a result in a combination of anger, jealously, revenge, pride or greed. But furthermore some murderers of a lower class mandate are a desire for control, revenge, and power. Frequently these factors when endorse is a potential of criminal activities of an individual. A criminologist would state that an incorporation of these factors is behind a person who has the mens rea in committing a crime. Also a murderer shall be classed in accordance to the manner of how the murder was performed and inflicted upon another human being.
The categorical area a murderer is put into is a serial killer, mass murder and spree killer. A serial killer is defined as individuals who have a history of multiple killing of victims who were usually unknown to them beforehand. Their crimes are committed as a result of a pressure that consistently has roots in the killer’s; a serial killer tends to commit a murder crime in one location and it was stated by Holmes and De Burger  .  Whereas a mass murderer commits murder of multiple numbers of people, this may be performed by a one person or a group of people.  The last form of murder killing is spree killing, spree killing is stated as a killing of two or more killing and commit murder in more that one location unlike serial killing and furthermore there is no break between the murders.  A murderer tends to commit crimes against a certain individuals for purposeful reasons.
The types of people a murderer would target to victimisation of murder are pensioners for valuable items, it is mainly a sociological reason being money and the reason they may be murdered as they can not be seen as fighting back for they life. A lowers class person between an age group of 16-20 year old are likely to commit crimes and are helpless to getting murdered depending on the crimes they are committing and babies are a constant treat as the current British official statistics on babies’ changeability increasing from a total of 15% in the period of 2008 and 2009  . This shows that babies are targeted as vulnerable victims. Furthermore The British crime statistics show that homicide has been at a high but is dramatically dropping, through out the period of that 2000-2009. The official statistics illustrates the figures decreasing from 1,047 to 615 homicides this shows that most murders have decreased but the factor that needs to be taken into account is that capital punishments were at a high death ratio within that period and the punishments of death penalties have changed dramatically as there are more helping public bodies providing support towards the police stopping a crime of murder before it transpires. Looking at the homicide statistics of crime it is categorised into manslaughter, murder and infanticide, so this does not provide an understanding on how murders tend to be committed without the two categories and does not distinguish how much murders are happening each year. The other factor that is raised from the statistics state that men are mainly being killed at a high level that women as the percentage of men being killed for homicide is 39 % whereas female victims homicide are at a percentage of 11%  . This illustrates that men are more likely to be killed than women regarding to murder. Some theorist would state that the results of these deaths come from sociological, biological functionalism theories. The history of theories helps distinguish what is the causation of crime and furthermore the performance of crime.
The theory of functionalism is a theoretical perspective of sociology. Sociology examines the situations in which people live and how these situations affect them. Some writers may state that the way a person lives should not affect the way a person reacts towards a high crime of murder. Sociology examines the question of why the world is the way that it is. Functionalism looks at society through a functional framework which stresses on everything; the functionalism method is an objective social world with similarity between the individual human being and society. Functionalisms look at the positivity of the society and always see the good in everything  . Some theorist may look at the point at looking at society as a positive way, this quote may not please peoples views towards positivity depending on what problematic issues people have been through in the past and furthermore people may not like the way society as treated an individual.
The biological positivist looks at the offender’s persons characteristics, this was popularised by the work of Lombroso  . Lombroso attempted to distinguish between different types of human individuals with classification of racial and biological differences. Lombroso wanted to establish a link between criminality by particular traits which correspond to various stages of human evolution. Lombroso stated that a criminal can be identified through a stigma of physical attributes such as, low intellect, high cheekbones and large ears, extra nipples, fingers or toes, an asymmetric jaw and finally tattoos, Lombroso had also stated that these criminals behaved in a different way for example low inability in the following factors, no social and moral issues, no differentiate between right and wrong, no guilt or remorse, no feelings towards other people and no form of any relationship.  So if a criminologist would look at Lombroso factors, there would be disagreements to the issues raised by the theorist as the physical features of a human should not be predicted or labeled when born of them physical attributes. This may amount to people being sentences do death without the need of any evidence enclosure. Furthermore people may get the physical features of what was stated by Lombroso as to accidents, which may label a person as being a criminal. So it was tested by Goring  on a group and there was no significant behavior but it was criticised that Goring did not have a proper control group and the criminal samples contained mostly mentally disturbed people but he also accepted the fact that the environment does contribute to the growth of criminal behaviour.  the legal theorist basically stated that the attributes lead to murder killers, as a result the tattoos where seen has being a issue that was raised and it shows that it as a affect on murders as it provided a understanding of how society use tattoos telling how much murders they have committed and what gang culture they are from for example, the Thailand gangs tend to use tattoos as a symbol for distinguishing what gangs they are from and furthermore the gang reputation.
In conclusion, after looking at the approaches of theorist and why people commit such crimes, it should be considered in real cases on whether or not punishment in the UK is effective or should consider using more fatal punishment similar to Capital punishment.
Robert Mochrie was a middle class worker, whose occupation was taking family photograph, taken when his wife Cathy was awarded a degree at Cardiff University, and also had four children in school. Robert Mochrie had realised that his Mrs Cathy was having another affair with another male sex named David Osborne from south Wales. He had stated that he had an intimate and sexual relationship with Mrs Mochrie. This caused the murders to result in murdering the family as it emotionally and mentally affected Mr. Mochrie to commit an unlawful act of murder.
Mochrie himself, killed the whole family in a hotel, Haverford west in South Wales because he hanged himself after murdering his wife, Cathy, along with Bethan, 10, Luke, 14, Sian, 16, and James, 18, in July last year. It shows that Mr Mochrie had affected the mental thinking which resulted in the actus rea of the crime  .
Looking at a criminologist prospective this case distinguishes that Robert Mochrie falls in the definition of a mass murder as an individual committed multiple killing one and if a theorist was to approach this scenario he or she would look at various theories to see what the causation of the crime. A theorist would firstly look at it form the prospective of functionalism theory as it states that as a couple they should stay together and work together, it shows relating back to the scenario that the situation that Robert Mochrie was the issue of Mrs Cathy indulging with someone else whilst in the presences of Mr. Roberts. This had an affect on the mental state has it resulted in committing the brutality of the family annihilation. It shows from the theory that it should look at things in a positive way, but in relation to the scenario Mr. Robert in this case could not take the issue that had happen in a positive way as it affect the thinking of what his wife had done and the mental thinking of Mr. Robert had not been take it into account that his wife would ever sleep with another man after being married and having four children which resulted in not allowing is wife to sleep with another man and in stopping this he committed the unlawful act.