1. Checking the authenticity of documents;

2. Determine the authorship of signatures, texts, and graffiti;

3. Elaborate a graphological study of personality;

4. Analyzing and extract a profile through digital writing;

5. Study bank documents as a means of payment (checks, credit cards);

Namely, it is about obtaining legal evidence from the scientific point of view with the aim of attributing responsibilities, resorting to expert and criminalistics techniques allied to technological advances.

For example, and using the graphological technique, our detective work is very useful in the Human Resources departments of companies in the phases of personnel selection. This is because this technique is being implemented more and more in entities as a complement to other traditional selection systems, such as the CV and job interviews. The advantage of this technique is undoubtedly the speed in the initial selection of cover letters, especially when there are many candidates because the results are obtained almost immediately. It is possible to obtain the maximum information of the candidate, such as predispositions, dubious or unfair behavior, intellectual potential, level of ambition, performance, maturity, personality, and sociability; as well as the aptitudes for the work in question.

Since the private investigation is a profession recognized by law in Spain, we, private detectives, are often called to testify before the courts, since our reports constitute evidence in judicial proceedings. In some of these investigations, we need to resort to forensic techniques to obtain the evidence. One of those cases refers to the determination of the authorship of signatures, in the investigation of their falsity, where the client affirms that it is false and intends, therefore, to demonstrate that said signature does not belong to him.

Increasingly the work developed by private detectives is directly related to forensic investigations and, as such, it is of extreme relevance that if the researcher himself has no training in this specific area he should resort to specialized professionals to obtain the necessary information in order to complete his report in an objective and impartial way to guarantee the maximum credibility.

The subject was exhibited as a poster at the 17th National Congress of Legal Medicine and Forensic Sciences held between November 22 and 24, 2018 in Coimbra, Portugal.