Criminology

A first degree murder conviction is based on two elements
Actus reus Actus reus is the act of killing another person. An actus reus is established by showing that actions or omissions by an accused person led to the loss of life.

Mens rea mens rea is the state of mind or the intent to commit the murder. The concept of mens rea in the context of first degree murder is meant to prove that the murder was commited with full mental knowledge of the accused. To prove mens rea, one needs to show that the accused had premeditated the act and that the accused is of a sound mind. Mens rea is meant to protect such persons who may commit the actus reus but may have done so because of reasons such as extreme provocation, self defense or other reason that does not qualify the act as first degree murder (Binder, 2001). Failure to prove mens rea therefore, may lead to the murder being classified as manslaughter, or may even lead to total acquittal.

Classification of murder
     Murder is a crime against person because it causes bodily harm to the victim.
Scenario
    Consider two people one known as A and the other known as B. A publicly insults B by telling him that is wife is a prostitute, even claiming that he (A) had slept with her numerous times. B does not react to As insults but instead walks away with an evident sense of bitterness. A week later B walks to As house and in full view of As family shoots him dead. The act will not be treated as manslaughter or that B could have been acting out of extreme provocation. The court will consider that for the one week between the time he was insulted and the time that he committed the act B was planning the act and that therefore will qualify as the mens rea to warrant a first degree murder conviction.

Robbery
Robbery is the use of force or fear in the act of stealing another persons property. The actus reus of robbery therefore has two elements
The act of stealing the property.
The use of force or violence in an attempt to intimidate, subdue or even kill a victim of the act.
The mens rea of the act is contained in two elements
The theft
The intention or the use of force in the act.
Classification of robbery
    Robbery is primarily a crime against a person and not property. Although a robbers primary intention may be to steal property the acts committed against the victim in the process more often than not overshadow the crimes against property (learnaboutguns.com, 2009). In some cases, the robbery act may cause a victim to lose his or her life or become traumatized and for that reason the focus ends up being the effects on the victims life and not on the property. 

Scenario
    While David was having dinner with his family, a man knocked the door claiming to have been from the neighborhood and in search of his cat. David opened the door to his neighbor and started explaining to him that they had not seen any new or strange cat in a while within their homestead. However, as he continued explaining to him that he had not seen any new cat in a while the man pulled out an object and held it against Davids neck, informing him that what he was holding was a knife. He threatened to stab David on the neck unless he was given two hundred dollars. David obliged and gave the man the money he had asked for. The man walked away but before he went far Davids wife shouted that they had been robbed, something that attracted the attention of the neighbors, which led to the combing of the neighborhood and the eventual arrest of the man. It later turned out that the object he was claiming was a knife was actually a lip balm he had taken from his girlfriend. However, the fact that he was not dangerously armed does not make his crime lesser than that of a robbery, he is still guilty of robbery.

Arson
Arson is maliciously setting fire on property. For an act of arson to be proven both acts must be proven, that is, the act of setting fire on the property and that the act was malicious. The act of proving malice is often the subject of investigation. The actus reus for arson are
Damage to property.
Endangering of property andor life.
The mens rea for arson is malice and recklessness.
Classification of arson

Arson is both a crime against property and crime against person depending on its nature. As stated before, the mens rea of this crime is mainly malice. For that reason, the classification of the crime will be dependent on the intent malice of the perpetrators. If the perpetrators committed the act with full knowledge that the property had people in it then it becomes a crime against person, while on the other hand if they committed the crime with the intention of only destroying properties then they are guilty of a crime against property.

Scenario
    A building hosting Johns private consultancy office caught fire and burnt down most of the property in the building. Consequently, the local authority decided to set up a tribunal to investigate and consolidate evidence regarding the fire. One of the key witnesses during the proceedings was Johns secretary, Jane. Johns business had not been doing well for a while and was even a subject of a fraud investigation, something that made authorities treat John as a major suspect. In exchange for protection and a possible relocation, Jane agreed to testify against John. She testified that John had behaved queerly in the week leading up to the fire and in particular he had refused to empty his trash can. As a result, his office was full of paper that he had no reason to keep around. On the material day, John was the last to leave office, a fact that was corroborated by the night guards. Ten minutes after he left office the fire started from his office and given that his office was on the upper floors it became hard for the fire fighters to reach the fire. John admitted that a cigarette butt he left could have started the fire. The tribunal did their own investigations and found that Johns firm was under investigation for massive tax fraud and therein they established that for John, the motive to burn down the offices and destroy evidence was enough to prove malice. The tribunal carried out its own investigation and found that Johns firm was under investigation for massive tax fraud and therein they established that John could have had the motive to burn down the office building. The desire to destroy evidence and admission of leaving a cigarette butt on his way out is enough to sustain a charge of arson.