Forensic science is the application of science to law. It entails the use of these scientific processes and methods in combating crimes. There are several branches of forensic science, such as: entomology, pathology, odontology, criminalistics, psychology, geology, computing, anthropology and chemistry (Dominick et al 2009). Forensic science comes in handy during investigation of fires, trace evidence, toxicology and forensic biology among others. The society has become more reliant on the laws governing the activities of its members. It applies to the technology and knowledge of science, as well as to the recognition of such laws. Arson is a malicious burning or attempt to the same. Although there are a number of issues of forensic concern, fire and arson still prove to be the most rife and dangerous nowadays.
This paper will look into the history of forensic science. It will also provide information on scientific changes and theories that have made significant changes when dealing with arson and fire. It will give a critical analysis on the successes and failures in the field of forensic science and arson. It will discuss advancements in technology, limitations of evidence with regard to gaining a conviction or acquittal, and offer predictions on the importance and limitations of law enforcement work concerned with forensic science and arson.
There have been several advancements in the forensic sector that have made changes in the criminal and victim cases. Just before the 1950s, there were police reports and case files. These were done on paper for evidence collection. Computers were developed in the 1950s which helped the police officers to store their data electronically. Nearly 2500 computers were in use in America by the mid 1950s. Out of these, the police department used a very small percentage. 911 was declared an emergency number in the year 1960. This has proved to be a major asset in the emergency department of police. Officers, fire trucks and ambulances can be dispatched through this system (David 2009).
DNA forensic analysis has been used in the linking of evidence to an individual. Based on various circumstantial events, DNA analysis can be used to solve a technical case. A case that can easily employ the DNA analysis system could be a case whereby a woman is reported missing and further information claims that she was last seen entering a car. The owner of the car then denies this fact. Forensic scientists will be forced to comb the car for any fibers, hair or any other material that may be used to identify the woman. This would help in establishing whether the woman died in the car or not, since the presence of hair in the car points to some sort of struggle. The owner of the car would then be apprehended.
The DNA strand for each individual is very unique and cases of similarities can only be seen in identical twins (David 2009). And the same is true of dental records and fingerprints. This technique has been extensively used in murder and rape investigations. Currently, the law demands that felons must give their DNA sample during incarceration. Criminal history could give the law some reasonable doubt or any probable cause.
The other advancement in forensics is computer forensics. Deleted files could be retrieved from the hard disc drive. This is usually done by an expert in computer science. Evidence such as child abuse, money laundering, child pornography and piracy in music can be located in some hidden files and used to build a case. With the advent of the Internet, the officers can monitor the sites that are considered dangerous to children (Bartol and Bartol 2010). Each computer is fitted with a digital fingerprint where officials can see those visiting a site and the time spent on the site. This technology has been used extensively in tracking child predators who have been avoiding the arm of the law. Computers have brought new opportunities, instant communications and modern possibilities. Information can be shared among the different departments at the click of a button. The gadgets have done a lot in the forensic department (Saferstein, 2005). This is because they have managed to eliminate unnecessary paperwork. All information obtained is stored electronically.
The term ‘fire investigation’ is a collective term that implies the assessment of a fire related incident commonly conducted by forensic investigators. This is done after the fire has been extinguished and the place declared safe to enter. A fire can be accidental, deliberate, undetermined or natural. Deliberate fires are considered arsons. Initial stages involve the investigation into the origin and cause of a fire or explosion. This is followed by ascertaining whether the fire was accidental or deliberate. Arson is classified into three categories called ‘degrees’. The first degree entails churches, homes and schools. The second degree entails unoccupied vehicles and structures. The third degree encompasses the burning of personal property.
The chemistry behind the burning of fire is a fundamental requirement to forensic scientists. Fires result from chemical reaction or combustion with oxygen, heat and fuel as requirements. It could be caused by mechanical, electrical, radioactive or chemical means. With oxygen concentration below 16%, the fire will be extinguished. Certain substances will burn with certain characteristic colors. Gasoline usually produces yellow or white flame with very black smoke. Wood produces red flame with grey smoke. Fire can spread through convection, radiation or conduction. Convection is the vertical spread while radiation is the general spread out pattern. Conduction involves direct contact (Saferstein, 2011).
Fire scene investigation is preceded by interviews of witnesses. These witnesses will provide very vital information regarding any individual seen within the site of the incident; they could also provide information about the color of the fire. All in all, any individual must be treated as a suspect. The scene is properly sealed before the examination and documentation begins. Fire burns in an upward and outward pattern which is always in a V- or U-shape. This can be used to trace the origin of the fire. Burnt materials, such as plastics, are a clear sign of an outbreak of a fire. Once that is done, the cause of the fire can be established. This implies that if the fire could have been accidental or natural, then the cause can be established to prevent any reoccurrence of such disasters. This would call for expertise from the electrical specialists. Accelerants are also commonly used in investigating fire causes (Lentini, 2005).
There are several indicators of arson used in the forensic field. Presence of fuel serves as a major indicator of arson. Doors and windows that are opened would suggest an arson activity as an individual was trying to supply the room with some oxygen to support burning. At the same time, an arsonist could try and conceal evidence by locking the doors and windows. When dealing with business arsons, lack of stock in the premise could be a clear indicator of arson. The same applies to individuals who remove important items from houses before setting them on fire (Lentini, 2005).
The use of accelerants is the major indicator in fire outbreaks. Kerosene, acetone, petrol, alcohol and diesel are widely used as accelerants in arsons. Multiple sites of origin of fire are indicative of the use of fuel in accelerating the fire. Investigators use electronic hydrocarbon detectors to locate fuels at the scene. They consist of vacuum pump that siphon vapor samples from the air. Two detection systems are currently available, such as the paper tape and electrochemical sensor. The paper tape employs the use of a strip of paper that will chemically react on contact with vapor. The electrochemical sensor operates by reacting a reagent with specific gas molecules. This is measured as an electrical current. The accelerant detection canines which are also called the arson dogs can locate the area where there is a high concentration of accelerant.
After locating areas with concentrated accelerants, the team then collects more samples for analysis. Samples could be obtained from the debris, floor and furniture. This is because these materials absorb the fluid that was used as an accelerant. Samples are well-sealed before being transported safely to the laboratory for further analysis. The accelerant can be extracted from the debris through the use of charcoal strips. It is heated in order for the sample to be trapped between the strips (David, 2009). A solvent is applied to separate the fuel residues out of the strip. From here, gas chromatography and mass spectrometry can be used at the analytical stage. Interpretations of the results require a lot of care and intensive labor. The investigator must also bear in mind that even household items may contain some percentage of petroleum products. This could be very misleading. Therefore, control samples are usually collected from the scene to prevent this from happening.