ABSTRACT
Objective To evaluate the effects of DNA examination of trace bloodstain samples from the scene collected with Trace Biological Evidence Collection kit. Methods Venous blood was made into bloodstains on the ground. The trace bloodstain samples were collected with Trace Biological Evidence Collection kit and common methods, respectively. DNA examination of trace bloodstain samples （50 from each group） was conducted on the constant temperature shaker for 2, 24, 48, 72, and 96 h, respectively, and the examination results of every group were compared. Results When the trace bloodstain samples were placed on the constant temperature shaker for 24, 48, 72, and 96 h, the DNA detection rates in the group which used Trace Biological Evidence Collection kit （100.00%, 100.00%, 100.00%, 96.00%） were significantly higher than those in the group using common methods （62.00%, 26.00%, 10.00%, 0）, the differences had statistical significance （P<0.05）. When the trace bloodstain samples were placed on the constant temperature shaker for 2 h, the differences of DNA detection rates between the two groups had no statistical significance （ P>0.05）. Conclusion The Trace Biological Evidence Collection kit can effectively improve DNA detection rate and extend detection time limit for trace bloodstain samples from the scene that have been stored for a relatively long time.
Subject(s)
Blood Stains , DNA , Forensic Medicine , TemperatureABSTRACT
Forensic palynology is to apply palynology to the field of forensic science, using pollen and spores to solve issues in juridical practice, such as civil and criminal issues. Sporopollens have a small size, wide distribution, diverse morphology, can be easily transferred, have durability, and is not easily noticed. It can provide strong investigation and related evidence for case detection as good trace evidence. The application of palynology in forensic science has achieved certain success, but it is underutilized in most countries. This paper analyzes the evidence value provided by sporopollen, collection of the sporopollen samples, the progress in detection technology and challenges ahead, based on the biological characteristics of sporopollen, combined with recent successful cases in forensic science, to comprehensively discuss the research progress in forensic palynology and its application prospects in forensic science.
Subject(s)
Botany , Forensic Sciences , Pollen , SporesABSTRACT
This is the case of a typical request for a chemical laboratory analysis to conduct a comparison of materials or trace evidence with completely unexpected results from those obtained if established protocols had been followed. This request involved the collation of black gunpowder, a material which is generally associated with firearms. In this case, however, the prosecutor's request was to compare the powder from two groups of paper used in tejo (a popular Colombian sport) in order to ascertain the identity of a homicide suspect at the scene of the crime.
A continuación se presenta una solicitud típica (cotejo de materiales) para un laboratorio de química o de evidencia traza, la cual tuvo una solución completamente inesperada y cuyo resultado fue más contundente que el que se hubiese tenido de haberla abordado según los protocolos establecidos. Esta solicitud involucraba el cotejo de pólvora negra, material que generalmente llega a estos laboratorios involucrado en hechos relacionados con el accionar de armas de fuegos. En este caso, sin embargo, la petición de la Fiscalía consistía en cotejar la pólvora de dos grupos de papeletas de tejo con el fin de asociar al sospechoso de un asesinato con la escena del crimen.
Subject(s)
Humans , Research , Criminal LawABSTRACT
Determination of sex is useful in Forensic Medicine. Barr bodies can be seen hair root sheath cells. The presence of barr bodies indicates that sex of the person is female. They are inactive X chromosome. The Barr bodies are also known as sex chromatin. Hair can present in the crime scene. Hair is trace evidence. The stain used was aceto-orcein. The percentage of barr bodies was found to be 28-49 %. The study was carried out for eight months and it was found that barr bodies persisted for eight months. It can be present anywhere at the crime scene. Hair of the accused can be present in hands of victim due to cadaveric spasm. Hair of victim can be found on the clothes of the accused. There is average fall in percentage of barr bodies with the passage of time due to the start of decomposition changes in the root sheath cells.
Subject(s)
Coloring Agents , Forensic Medicine/methods , Hair , Humans , Indicators and Reagents , Sex Chromatin/analysis , Sex Chromatin/diagnosis , Sex Determination AnalysisABSTRACT
In the field of the forensic medicine, deciding the cause of the injury is very important. Forensic doctors usually use their naked eyes, two dimensional photos, the characteristics and the distribution of the wounds for evaluating the cause of the injuries. After body release, forensic doctors not infrequently met the questions from the law enforcement whether the injuries were matched with the new facts or statements given through the progression of the investigation. In the face of answering this question, the information or evidence about the injury is insufficient. New technologies and instruments are being developed and will be helpful for getting the evidence from the human skin injuries. In this preliminary study, authors try to find the usefulness of appraisal techniques(3D scanner, trace evidence, TMDT, alternative light) that are already used for other purposes in forensic field. These techniques have their own merits for preserving the evidences from the injured skin. But further studies and systemic approaches are essential for more scientifically verified evaluation of the cause of the skin injury.