Analysis of Non-Biological Evidence in Forensic Investigation


Analysisof Non-Biological Evidence in Forensic Investigation

Analysisof Non-Biological Evidence in Forensic Investigation

Theworld has been experiencing its fair share of crime in the recenttimes. Of course, there are variations in the types and magnitudes ofcrimes that are experienced in the different parts of the country andthe globe at large. On the same note, the rates of crimes indifferent parts of the country at different times have always beendifferent as a result of varied aspects. Nevertheless, it has wellbeen acknowledged that crime of any nature always has a negativeimpact on the wellbeing of the economy of the part affected and thecountry at large. This has necessitated that the country makes animmense investment to its investigative capacity to as to ensure thatcrimes are solved, the culprits apprehended and made to pay for thecrimes, and the victims assuaged. Needless to say, the investigativecapacity of any police force is fundamental to the resolution ofthese crimes (Bisset et al, 2002). As a result of the persistentefforts to enhance the quality of investigations that are done, bothin terms of efficacy, speed and accuracy, there has been immenseadvancement of forensic science. Further, it is worth noting thatforensic science, while being quite fundamental to crimeinvestigation, is divided into varied categories one of which isvirtopsy.


Theterm “Virtopsy” is derived from blending the words “virtual”and “autopsy”. Autopsy (or obduction, autopsia cadaverum orpostmortem examination) underlines a highly-specialised surgicalprocedure that involves a systematic examination of a corpse so as todetermine the manner, as well as cause of death, as well as assessany injury or disease present. Virtopsy refers to a bloodless, aswell as minimally invasive virtual autopsy procedure that is used inthe examination of bodies for the causes of death. It particularlydetects bullet paths, internal bleeding, as well as hidden fracturesthat may be impossible or difficult to find in conventionalautopsies. MRI and MSCT procedures assist in the picturing of thebone and missile fragmentation, gas embolism, brain contusion,fracture patterns, 3-D bullet localization, as well as bloodaspiration to the victim’s lungs. Virtopsy differs from traditionalautopsy in the fact that it does not tear down human tissue (Thali etal, 2003). Of particular note is the fact that the developers of thistechnique did not aim at having the procedure replace theconventional autopsy rather it was environed as a tool that would beused in instances where it would not be feasible for the body to bedissected or in cases where it would be difficult to visualizeforensic evidence.

Relevanceof Virtopsy in Forensic Investigation

Therelevance and importance of virtopsy cannot be gainsaid as far as theenhancement of the efficiency of forensic investigation is concerned.Indeed, this may be evidenced by its increased incorporation inexamining a large number of crimes especially where the investigationrevolves around a death. Virtopsy technique involves the use ofcontemporary radiographical aids such as computed tomography (CT), aswell as magnetic resonance imaging (MRI) in scanning dead bodies andgetting more accurate, specific, and sensitive results compared tothose of conventional autopsy. Indeed, comparison between traditionalautopsy and the virtopsy techniques such as CT has indicated that CTwould be a considerably more superior technique for identifying theentry and exit patterns pertaining to wounds or rather the fracturepatterns, as well as gross tissue injury and pathological gascollections. Indeed, CT has been shown to be an extremely valuabletool in forensic investigation, especially in the demonstration anddetection of foreign bodies, fractures, as well as gas and/or air(pneumothorax) (Aquila, et al, 2013). Of course, it is wellacknowledged that postmortem CT may be considerably less sensitiveand specific in the evaluation of intravenous contrast. In essence,it may be complemented by postmortem MRI, which amounts to a highlyspecific and sensitive tool, which may also be utilized in theassessment of soft tissue injuries, hematomas, neurological ornon-neurological trauma, as well as contusions. Scholars haveunderlined the fact that radiologic virtual autopsy would come inhandy as an easy examination pertaining to bodies that arecontaminated by radionuclides, infection, and toxic substances amongother biohazards (Thali et al, 2007). In addition, virtopsy allowsfor the 2D and 3D postprocessing, which is known to immensely allowfor the visualization of findings to individuals that are not present in the course of the examination such as courts officials.Indeed, the combination of techniques of 3D/CAD photogrammetry andradiology comes with the advantage of being non-invasive,non-subjective, observer-independent, as well as digitally storableand transferable for a long time so as to obtain second opinion. Thiswould allow for matching of the offending object or weapon used incommitting the offense. On the same note, the use of postmortemangiography would allow for the visualization of the entirecardiovascular system. In instances where there exist injuries to avessel, the surrounding tissues would have dye spillage, in whichcase minute blood vessel injuries to capillaries may also bedetected.

Implicationof Virtopsy in line with NAS Recommendations

TheNAS has come up with a number of recommendations aimed at enhancingthe role that forensic science in investigations. The report wasaimed at providing a way forward for the identification of potentialscientific advances that would enable law enforcement agencies to useforensic techniques and technologies in the protection of the public,investigation of deaths and solving of crimes. One the same note, itwas aimed at outlining the guidelines and best practices regardingcollecting and analyzing forensic evidence so as to safeguard qualityand consistency in the utilization of forensic techniques andtechnologies. However, there are questions regarding the implicationsof virtopsy in the context of the recommendations. While there may bevarying opinions, it goes without saying that virtopsy is thefulfillment of quite a large number of these recommendations.

First,virtopsy would allow for an increase in the accuracy and efficacy inthe examination of crimes so as to allow for determination of mannerof death and enable apprehension of culprits. The 3rdNAS recommendation underlined the necessity for increased research soas to address issues pertaining to validity, reliability and accuracyin forensic science disciplines. The second part of thisrecommendation underlined the need for studies of accuracy andreliability of forensic techniques to be a reflection of actualpractice done on real case scenarios (National Academies of Science,2009). This is especially seen in the use of CT Imaging in detectingforeign bodies. It is noted that metals have a higher detection andlocalization capacity when in the body as they have higher x-rayabsorption in comparison to soft tissue and bones. This fact bearsimmense usefulness in forensic science for numerous reasons. Ininstances where the crime involves gunshots, MSCT scans would easilydepict any remaining projectiles in the body. The reconstruction ofsuicides and homicides necessitates an accurate localization of suchbullets. In instances where the bullets disintegrate, it may bedifficult to find them in conventional autopsy. This is whereMSCT-scan would come in handy. Indeed, MSCT-scan data may be comparedto the images of radiological images pertaining to the deceasedperson carried out antemortem. MSCT-scan would allow for completedental profiling through the creation of panoramic dental images thatmay, then, be compared to the deceased person’s data with thedentists.

Inaddition, virtopsy would allow for elimination of bias ininvestigation and examination of crime scenes. In its 5threcommendation, the NAS stated that it is necessary that the NIFSencourages research programs regarding observer bias, as well asother sources of human error. While the research programs would allowfor the quantification and characterization of the amount of error,the main aim is to enable the maximum minimization of likely bias, aswell as sources of human error in forensic practice (NationalAcademies of Science, 2009). This is especially the case in theidentification of bodies, which is a prerequisite before anypostmortem investigation. It is often difficult to re-establish theidentity of unidentified bodies. Scholars have noted thatmulti-detector row CT would be immensely helpful in this case. It isonly possible to carry out a secure postmortem identification basedon fingerprinting, dental status or DNA profiles. However, DNA comesas extremely costly and time-consuming, in which case dentalidentification and fingerprinting are the most common (Dirnhofer,2006).Cranial CT data derived from corpses would allow for reconstructionof any antemortem radiographic progression that would be used forcomparison. Further, the restoration material used may be ascertainedbased on postmortem CT data and correlated with antemortem dentalrecords pertaining to suspected missing persons (Dirnhofer,2006).Apart from the gross morphologic findings like endoprosthesis of theknee, hip and should, which are usually already expected based onefficient external inspection, a whole-body corpse CT would revealnumerous findings that may be used in the exclusion of assumedidentity and positive identification, which may not be attained inroutine autopsy (Dirnhofer,2006).This would eliminate any possibility for errors and bias especiallytowards any pertinent cases that the investigators may be handling ata particular time. This is also the case for CT imaging and detectionof fractures. It is noteworthy that cross-sectional images may beused in diagnosing fractures in clinical radiology. Of particularnote is the importance of the pattern and form of fractures inforensic medicine as they would provide information regarding theorigin of trauma. CT imaging may allow for 3D-reconstruction, whichwould be crucial to informing investigators regarding the side fromwhich the impact that resulted to the structure emanated, andpossibly, the instrument that caused the injury (Grabherr, 2007). 3Dfracture models provide proper overviews pertaining to skeletalinjuries while showing them in ways that even medical laymen wouldcomprehend, thereby facilitating collaboration between investigators,forensic pathologists, justice and police. Further, CT data may allowfor easy detection of small fractures.

On the same note, virtopsy may be seen as an improvement of theconventional autopsy, especially considering the deficiencies thathad previously been identified regarding such procedures. The 6thNAS recommendation stated that it was necessary that tools aredeveloped for enhancing the measurement, validation, informationsharing, reliability, as well as proficiency testing in forensicexamination. Further, it underlined the necessity for forensicscience disciplines to be self-correcting enterprise that developsand implements feedback loops that enable the profession to learnfrom past mistakes (National Academies of Science, 2009). It is wellacknowledged that conventional autopsy may take no notice of minutefractures or injuries. Further, information so derived may not beeasy to share without being challenged. Nevertheless, the advent ofvirtopsy and specifically 3d Surface Scanning and DigitalPhotogrammetry is testament to the self-learning capabilities offorensic science and the persistent improvement in its validity,reliability and information sharing. Digital photogrammetry is usedalongside the highly accurate 3D surface scanning in documentingexternal findings, as well as injury inflicting instruments. Thedigitization of any object involves two steps. First, photogrammetrywould be carried out so as to predefine its discrete points. Inessence, reference targets, as well as coded markers and coded scalebars would be applied to the object. After this, a number of imageswould be taken from varying views with the photos being transferredto computers where the TRITOP software would calculate the referencetarget’s 3D coordinates. The second step in the process ofdigitization of the object is 3D surface scanning, where thereference targets merge the single scans that were done from varyingangles around the object automatically to complete 3D data set. Onthe basis of the principle of triangulation, the 3D coordinatespertaining to 4 million surface points per measurement would becalculated using scanning software ATOS. These digitizing techniquesresult in real-data-based 3D models pertaining to the body’ssurface, a weapon and accident car in real color. Of particular noteis the fact that even the smallest defects or injuries would bedisplayed in the model. Such models are used alongside radiologicaldata in the reconstruction of homicides and accidents. Thereal-data-based reconstruction, for instance, may be used incomparing patterned gunshot injuries to firearms obtained from thecrime scene, with the presumed gun’s 3D model being merged to theinjury’s model, thereby allowing for derivation of proof of the gunas the one that caused injury, as well as demonstrating the gun’sexact position during firing. On the same note, the 3D surface datamay be used in reconstructing the course of a particular accident,where the impact situation would be carried out through comparison ofthe individual’s injuries to the defects pertaining to theinflicted car.

Restrictionsin the Use of Virtopsy in Forensic Investigations

Likenumerous other emergent and experimental technologies, there existsignificant positive and powerful negative aspects. This is the casefor virtopsy, whose positive aspects have been well acknowledgedincluding enabling pathologists to detect bullet paths, hiddenfractures and internal bleeding, which may be difficult to isolate.MRI scans and CT scans would outline the emboli, which are the airbubbles that get into the body via the wound and hinder or obstructblood vessels. Scholars have noted that such evidence may escape assoon as pathologists cut open the organs or veins, therebynecessitating that underwater autopsies are carried out so as to seethe air getting out (Bolliger et al, 2008). Virtopsy scans would easethe detection of inhaled or aspirated water, as well as blood inone’s lungs, which would inform the pathologist that the individualwas alive when he sustained the injuries or got into the water. Onthe same note, such scans would enable the pathologist to efficientlyget the bullet, as well as other fragments lodged in the body as theywould indicate the exact location of the fragments withoutnecessarily cutting the body open and looking for them (Aquila et al,2013).

However,there are a number of troubling restrictions or limitations to theapplication of virtopsy in forensic investigations. First, virtualautopsy is incapable of diagnosing deaths occurring naturally orcaused by heart failure, poisonings and infections. Indeed, scholarshave underlined the necessity of coming up with special techniquesthat would allow for the use of computers in accurately interpretingbody scans considering the body condition. It is worth noting thatMRI machines functioning may be hampered by the cold temperatures ofthe body as a result of the slowing down of nuclear vibrations. Onthe same note, it is well acknowledged that the images generated orproduced in the course of CT scans and MRI imaging may be subject tomanipulation and interpretations since they are computer generateddigital images. This would particularly limit the use of suchevidence in court with scholars in criminal justice and criminologyunderlining the fact that any time the jury is offered somethingother than the real thing, it is being given an opportunity tointerpret it (Tejaswi &amp Hari Periya 2013). This introduces thepossibility that the argument that the evidence has been manipulatedwould be misconstrued as more viable, something that would neverhappen when the jury is being offered the real thing. It isunfortunate that American justice systems have been particularlydependent on real physical evidence, while virtopsy would be implyingthe elimination of real evidence in favor of digitized one. Further,it is noted that traditional pathologists utilize all their sensesapart from taste so as to obtain complete comprehension of theconditions and processes of the body, something that would not bepossible in the case of virtopsy (Grabher et al, 2009). On the samenote, there are questions pertaining to the possibility of scansdetermining tumor types and infectious agents. Of course, it is wellacknowledged that in the case of endocarditis, transthoracic ortransesophargeal echocardiography would play a crucial role invulvular vegetations’ diagnosis. Indeed, postmortem MRI wouldclearly indicate cardiac valves vegetation with sufficient contrastand deficient of motion artefacts. However, it has been noted thatthe MRI scans may not be capable of determining other infections andtumors.

Whilethere may be limitations to the use of virtopsy in forensicinvestigation, it is worth noting that the technique was crafted as away of complementing conventional autopsy. This means that there arestill some things that would have to be done in the conventional ways(Christe et al, 2010). Of particular note is the fact that thelimitations do not negate the efficacy in the use of this form oftechnology in forensic investigation, especially considering itsaccuracy and speed (Dirnhofer et al, 2006). Indeed, it is often morepreferable especially where there are religious concerns pertainingto splitting open the body. The minimally-invasive aspect of thistechnique makes is more applicable to a large number of societies.

Conclusionand Recommendations

Itis evident that the use of virtopsy would be crucial in enhancing theefficacy of police or forensic investigations. Indeed, suchtechniques come in handy in allowing for the determination of themanner and cause of death of murder victims in a speedy and accuratemanner. Unfortunately, there has not been much uniformity in theadoption of forensic best practices across different countries oreven agencies, which challenges the application of this technique.Further, the instruments used in this exercise are almost alwaysexpensive, which limits the possibility of being upgraded(Oesterhelweg et al, 2009). The service of forensic practitioners tothe goals of justice is dependent on the efficacy of theirinstruments, in which case it is imperative that upgrades of thesystems is sufficiently funded and unified. On the same note, itwould be recommended that further research is carried out so as toaddress aspects such as validity, accuracy and reliability in variedforensic science disciplines and allow for enhanced application ofthe same in courts of law as a replacement or substitute of the realthing. Such studies pertaining to the accuracy and reliability offorensic techniques should be a reflection of actual practice done onreal case scenarios (Christe et al, 2010). Further, such studiesshould underline the limits pertaining to accuracy and reliabilitythat would be achieved by analytic techniques irrespective of thevarying evidence.


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Theincreasing rates of crime have always had negative impacts on thewellbeing of any country’s economy. It is well acknowledged thatthe capacity of law enforcement agencies to investigate andaccurately determine the circumstances of crimes has a bearing on thepossibility that culprits would be apprehended and confidence onpolice force restored. In this regard, there have been persistentefforts to enhance the accuracy and efficacy of investigators, withforensic science coming as one of the most fundamental. In instanceswhere the death of an individual is suspicious, it is common forautopsies to be carried out. However, these can be cumbersome andpretty limiting with regard to detecting some anomalies such asfractured bones or ruptured capillaries and arteries. This is whatgave rise to virtopsy, which would involve minimum invasion on thebody, with images being taken on it, thereby allowing fordetermination of causes, manner of death and object used. Variedtechniques are used in virtopsy including CT scan and MSCT, MRIImaging, which are complemented by 3d Surface Scanning and DigitalPhotogrammetry. Nevertheless, this technique is still limited withregard to the uniformity with which forensic science is carried outin different law enforcement agencies, as well as the high cost thatwould be incurred. On the same note, ensuring that such data isadmissible in court may be difficult as defense may cite thepossibility for manipulation of digital images. In essence, moreresearch would be needed to eliminate these limitations and enhancethe accuracy and efficacy of the techniques, as well as theuniformity of their application.