Forensic scientists are people who using different scientific methods and modern laboratory techniques study compare and interpret found traces, and put them in direct connection with certain offenses. Forensic experts are highly specialized persons engaged in the investigation of crimes and accidents. Thus, with application of expertise in various fields, including chemistry, biology, physics and medicine they find physical evidence at the crime scene and try to understand what has actually happened and who the perpetrator is. We can conclude that forensic are also scientists because they, like all the other scientists rely on scientific methods. Criminal justice students are quite familiar with the practice that a forensic scientist firstly take notes, observes and then collects the data. After collecting all the data he processes them in his laboratory, and on that basis he presents his theory of the event he investigates.
The success of forensic investigation depends on the forensic scientist, technical equipment and preparatory activities. Except the degree in criminal justice a forensic scientist is required to have personal and professional experience and certain characteristics as curiosity and tendency to experimenting. He must constantly monitor developments in science and practically apply them into his work.
Forensic scientists list specific issues into the police report which are related to a specific cause (trace), and additional information relevant to the course of investigation: a description of the place of event, conditions in which the traces were found, the way they were handled, and a list of all the circumstances of comparative material. After the conducted forensic analysis the forensic expert gives his opinion and finding, which at that point have legal force in the form of material evidence in court.
During the investigation, forensics examine the clues found at the crime scene with various physical and chemical methods to determine their characteristics and identification. While testing and measuring using physical methods, properties of matter do not change and they do not destroy the sample submitted. Usually these methods are thermo analysis, methods of light reflection, etc. They are using quantitative and qualitative analysis, thin-layer and gas, chromatografia, different probes for detection of explosives and narcotics, DNA analysis, etc.