Realizing Reliability in Forensic science

Forensic science is the application of science that deals with identification, collection and investigation of pieces of evidence that are found in criminal and civil cases for the court of justice. This field offers various safety measures, reliability factors, standards & guidelines concerning the credibility of evidence in both criminal and civil trials.

For years now, the TV series, movies and media showed the misconstruction of solving the heinous crimes by the forensic experts in a very nice and tidy manner. The fictional TV shows like CID, CSI portrayed how the crime committed, the evidence is gathered, samples are analyzed in a forensic science laboratory and the culprit is caught and prosecuted--within an hour. Although in the real world, forensic science plays an incredible role in investigating and solving crime but in a very different manner than the reel world.

 

 

DNA Analysis

Examining and interpreting the DNA profile of an unknown individual has become the most trusted method in Forensic science. However, a DNA sample had to encounter substantial experimentation and techniques to become reliable evidence. The experimentation starts with 1) the isolation of the DNA from the DNA sample of unknown and known origin, e.g. blood; 2) processing of the DNA to obtain the results; 3) the determination of the specific region of DNA and variations in the DNA; 4) the comparison of the test results from the unknown and know DNA samples.

 

This process of making DNA sample reliable includes 'biology' which involves collection of sample; 'technology' which involves Polymerase chain reaction, slab gel, capillary electrophoresis which makes millions of copies of DNA sample and separates segments of DNA. 

 

 

Hair/Fiber Analyses

Analyses of hair samples can tell us the presence of a specific individual at the crime scene, whether it is human or animal. The hair and fibre samples are tested using microscopic comparison and chemical analysis. The microscopic comparison identifies the shape, texture, color, texture and other aspects of the sample, while chemical analysis indicates the presence of toxins, drugs, and other chemicals. According to some studies, microscopic analyses of hair and fibre is not yet an accurate science, thus deciding a case on hair and fibre analysis may lead to unjustified convictions.

 

Practice in escalating reliability

 

 

Reproducibility of evidence

Some evidence requires reproducibility of results which means re-testing of evidence. In some criminal cases, it is very important to reassure that 'Does re-testing of the same sample under the same environmental and instrument conditions return the same result consistently as the previous one'?

 

 

Improving errors

It's a good practice for a forensic expert to improve accuracy while doing the measurements to reduce the errors. For example, in case of measuring long bones of a skeleton on an osteometric board, it is very important to be precise with the readings for further analyses.

 

 

Calibration of instrument

While using different analytical instruments like GC, GC-MS, HPLC, HS-GC-MS to analyze the chemical evidence, always calibrate and check the instrumental parameters and conditions. For example, loop temperature, oven temperature, transfer line, vial equilibration, pressure equilibration, etc. to reduce the errors in the result. 

 

 

Reporting of results

It is mandatory in most fields of forensic science to increase the standards of writing the reports about the results of investigating and their findings. The reports that are presented in a court trial should be complete & thorough. They should outline the materials & methods, procedures, the technique used and conclusion of analyses that they have drawn using minimum words to make prosecutors, defence attorney and judge understand.

 

Forensic science can be used as the part of the case in solving the crime but it cannot be used as the whole case in proving someone's guilt. The reliability of forensic evidence also depends on the forensic experts who are responsible for analyzing the evidence and the accuracy of the instruments they are using. Some of the forensic techniques may require more accuracy to grow the reliability of evidence in the court.