Differences Between Organic & Inorganic Forensic Evidence

Differences Between Organic & Inorganic Forensic Evidence

          The objects and/or information that may be submitted into court for judges and juries to put into consideration during the hearing of a case are referred to as evidence. Evidence can be viable and can serve various roles in an investigation like tracing an illicit substance, identifying remains or even reconstructing a crime. There are different types of evidence depending on the origin or source of the material. For instance, it can come from genetic material, trace of chemicals and even dental history or fingerprints. In order to begin any forensic analysis, the suspected evidence and the elements are separated into organic and inorganic compounds. Evidence is said to be organic when it contains carbon in combination with hydrogen, nitrogen, sulfur, chlorine, and bromine. Inorganic evidence does not contain hydrogen, nitrogen and other elements but mostly contain non biodegradable chemical compositions. Most of the compounds analyzed in crime laboratories are organic.  There are various techniques used to find out whether the evidence is organic or inorganic. Some of them include; spectrophotometry, chromatography, mass spectrometry, electrophoresis, et cetera (Saferstein, 2011).  This paper analyses differences between organic and inorganic evidence concerned with forensics in the Criminal Justice System.

Strengths and Weaknesses of Organic and Inorganic Evidence

          Organic substances are more as compared to inorganic evidences in the juries. Examples of these organic evidences include hair, biological fluids, drugs as well as explosives as all of them contain carbon. Inorganic substances comprise of; gun powder, glass paint, most dirt and most dirt among others. Most of these evidences are real and tangible and they are at times described to speak for themselves because they can be carried to court rooms and be seen directly during the hearing of cases. For instance, if the accuser committed the crime of killing using a gun, the gun can be used to trace the particles found at the scene of the crime, finger prints, handwriting, shoe print and the recovered property among others. Organic and inorganic evidence is part and parcel of solving crimes as it can be witnessed and confessed. In the absence of the two evidences or one of them, it will be quite hard to find even the suspects of the crime (Saferstein, 2011).

          For example, incase of an explosion, and no explosive material is found in the scene, inorganic evidence may not assist much. At this point, an expert will be required to intervene. He will analyze various extracts at the scene to capture any organic residues present. The extracts will be analyzed to employ the exact instrumentation used to explore. The end results may differ in their specificity, and so the expert will be required to play a great role of interpreting the results properly applying his knowledge on the composition of explosives the reaction and the end products after exploding.

          Organic evidence can be tested by various chemical reagents to detect characteristics of chemical components like carbon. For the case of explosives, chemical reagents like diphymlymine and potassium hydroxide serve as indicators of showing reactions of color. Optical microscopes also provide means of observing directly the physical characteristics of particles like fibers and hair. Microcrystalline components can be identified by use of x-ray diffraction to detect characteristics structure of the compound and the nature of crystalline order.

          For organic evidence, identification of unknown chemicals becomes quite challenging as observing whether the chemical is solid or liquid reduces the number of compounds in the substances. For instance, mechanical properties aspects considered include plasticity, elasticity, compressive strength, shear strength, indentation hardness and ductility among others. Inorganic substances can be identified through the use of atomic absorption, neutron activation analysis and atomic emission and x-ray fluorescence (Saferstein, 2011).

Generating Fingerprinting of DNA

          DNA testing is one of the commonly advanced and mostly used in forensic sciences today. It is used in rape cases, sexual assault and other kinds of homicide cases. The DNA can be used in semen, skin, blood, hair, and saliva through the process of DNA typing or profile and finger printing. The Polymerase Chain Reaction (PCR) is used to replicate the DNA molecules in vitro. As a result, the replicative amplification technique is applied to assist in the comparison of lengths of repetitive sections of DNA like the Short Tandem Repeats (STRs) for fingerprinting genetics. There are highly variable repeat sequences of exploits referred to as mini satellites, it is very easy to identify a match that would not have a risen by coincidence unless it’s a case of identical twins with identical genetic profiles. This method I sense has proved to be very reliable in identification of criminals (Fisher, 2000).

          The forensic scientists must always ensure that they work under hygienic conditions to reduce sources of error that might distort the evidence discovered. Once the evidence is collected, it is packed, labeled and transported by the police to the lab. In the laboratory, the evidence is logged in and then given an identification number, next it is placed in storage far from mixing with other evidence and later analyzed by the forensic scientist. The evidence is virtually inspected and described appropriately to document its conditions.

          Suspects of various crimes are asked to provide samples of DNA for database which assists investigators a great deal in solving previous cases where only DNA samples were gotten from the scene leading to various post conviction exonerations of suspects who had been convicted before. DNA is also used a great deal to identify remains of humans, marching organ donors, paternity testing, to establish the composition of foods, to study the populations of wild animals and in the identification of victims who suffer mass casualty incidents.

          I sense DNA typing has been used a great deal in identifying the remains of victims of terrorist attacks like the world trade centre twin towers collapse, the scandal of Clinton Lewinski et cetera. DNA has also assisted a great deal in revealing men who father children and deny them or hide abandoning them. An example is Thomas Jefferson who fathered a child with one of his African –American slave. Scientists have used DNA to bring dinosaurs from Jurassic era to life which has added value and preserved dinosaur blood preserved inside insects and encased for a long period of time in organic amber (Fisher, 2000).


          Forensic scientists depend on organic and inorganic evidence with physical properties of compounds and chemical elements to identify bombs, explosives, and fluids like semen, blood, and saliva among others. They have also identified genetic materials like computer files, DNA and other controllable substances like fingerprints, hair fiber, glass, paint and voice print among other identifications.

          The crime laboratories have also assisted much in detecting these chemical elements and compounds through five basic services that they offer. These services include; physical science unit, biology unit, firearms unit, the document unit and the photographic unit. Some modern laboratories have got services like toxicology, voice print analysis, polygraph administration and finger print analysis in addition to the five units. From the arguments above, it is very clear that, both organic and inorganic evidence are very important in the identification of crimes as well as the criminals. Continuous training and educating forensic officers and investigators on methods of collecting and preserving organic and inorganic evidence at the scenes of crime is very important. This is for the sake of developing the field and improving security matters worldwide (Conklin, Shortelle & Gardner, 2002).


Conklin, B., Shortelle, D. & Gardner, R. (2002). Encyclopedia of Forensic Science. NewYork: Oryx Press.

Fisher, B. (2000). Techniques of Crime Scene Investigation. Boca Raton: CRC Press.

Saferstein, R. (2011). Criminalistics: An introduction to forensic science (10th ed.). Upper Saddle River, NJ: Pearson Education, Inc.