Most of the time when crimes are committed, the criminal leaves physical evidence behind, for example, documents, fingerprints, DNA, etc. Documents are the most probable evidence when it comes to forensic auditing.
The best opportunity to collect evidence is at a crime scene, sometimes giving the investigator the only opportunity to recognize, collect, and record physical evidence.
Investigators should recognize, collect, and record evidence as they see logical or relevant to a case, as there are no rules to what may be collected as evidence, but the evidence collected has to have scientific and legal value. Because physical evidence is extremely important in a legal proceeding, investigators should be familiar with the basic principles and procedures surrounding physical evidence and should be able to collect and preserve this evidence competently.
Experts are needed to process some evidence such as fingerprints or any other laboratory related processes, documents on the other hand need little or no processing, and it is crucial that an investigator collect, package and mark, and identify all the relevant evidence needed to investigate a case successfully. The evidence collected has to be given in court, if called upon to do so.
The following process is used by the South African Police Service, although its not the only acceptable process to collect evidence and present it to court, it is a good guideline to forensic auditors:
According to the Locard principle, all crime scenes have evidence, and as soon as a forensic investigator arrives at a crime scene, he/she should start looking for any physical evidence related to a crime. It is crucial to collect and package all evidence for storage, as the original files should be copied and the copies should be used in an investigation instead of the originals. The reason for this is that dockets get lost and stolen, and if the original evidence was included in the docket, the originals will be gone, and the case will most likely be lost.
It is crucial to ensure that evidence is preserved and protected by safeguarding it until it is necessary to provide the collected evidence in court, so that no evidential losses are suffered in a case. The steps taken to preserve evidence from being tampered with must also be recorded as it may be required in court.
Examples of recording physical evidence are by use of photographs, sketches, video tapes, voice recordings, and written notes. The recordings of physical evidence of a crime scene are an assurance that the evidence is reliable and can be presented successfully in court. Recordings must contain a date, location, time, and the persons at present.
Packaging evidence depends on the type of evidence, for instance, documents can be preserved by placing it in a plastic sleeve, evidence such as fire arms can be preserved in a paper folder, and small evidence can be placed in small plastic zip-lock bags, ensuring that the evidence does not get tampered with or contaminated.
Samples that have to be compared should be separate from examples that have to be analyzed, for example hair samples. A piece of hair should be sent to a laboratory for analysis to determine what specie the hair is from (dog, cat, human) and what other substances are found on the hair (chemicals, fibers, dirt). Another sample of hair should be preserved to be compared with the hair of suspects or victims.
The less people handle evidence, the better it is preserved. The less people handle samples before and during packaging, the better the sample will be preserved, giving clearer indications during analysis or comparison.
Evidence should be kept in storage for a minimum of five years after the case has been closed, because the case can be reopened due to new evidence found or a new investigation related to the stored evidence. Stored evidence should have an index number with a detailed description about the inclusive exhibits for easy referencing.
5. Marking physical evidence:
All evidence should be marked with an exhibit number, as soon as it is discovered, in such a way that it does not deteriorate or harm the value of the evidence. The exhibit number should also be documented so that you can refer back to it, with regards to the location it was found and how it fits into the puzzle pieces of an investigation, when the exhibits are presented in court.
Personally, I think all evidence should be placed in a folder or plastic sheet or zip-lock bag with an exhibit number tagged or labeled on the container. Writing an exhibit number on a document might influence the evidential value, and should rather be done on a copy of an evidence document.
6. Preservation of integrity:
Constantly safeguarding evidence assures the court that evidence or exhibits have not been tampered with, keeping the evidential value in tact is a high priority from when it is collected until the time it needs to be presented in court and accepted as evidence. Convincing the court that the evidence has not been tampered with, I think, can be gained by documenting where evidence has been stored or locked up.
7. Maintenance of continuity of possession:
It is crucial in a court proceeding that evidence is not questionable but reliable. By making sure that a minimum amount of people handle evidence, and that all persons who handled the evidence in question are recorded, the evidence stays highly reliable.
Although evidence may be collected, marked, packaged, and sealed in accordance to court standards, doubt in the persons who handled the evidence may make the evidence questionable, which is why the integrity of physical evidence is so crucially important to a forensic investigator.
All persons who handled evidence have to appear in court and testify about the condition of the exhibit whilst they handled it.
8. Presentation in court:
The forensic investigator who collected evidence will be asked questions in court by the court and the defense about the evidence presented. The investigator will also have to identify and confirm the evidence and the relevance to the case.
When the evidence is presented successfully and the questioning has gone successfully, then only will the court accept the evidence as reliable and relevant.