Evidence: How private investigators can help lawyers

A private detective will be able to assist a lawyer in many situations where the truth needs to be discovered and proven. These private practitioners have become a great alliance for law firms. Nowadays, many of the lawyers who have worked with a private detective tend to repeat the experience thanks to the good results achieved with their investigations.

The possession and availability of evidence is fundamental to the conduct of litigation. Many lawyers, private individuals and even companies, whether multinational or national, have realised that having a private detective can mean winning a court case. Judges rely on facts and evidence, we can never prove a fact without evidence.


Many associations, such as the Professional Association of Private Detectives, collaborate with the Bar Association, as in this way, both can provide greater coverage to all their clients. Recall that the evidence adduced at trial is the basis for legal arguments. In such cases, the judge will rule in favor of the evidence presented. The Spanish Supreme Court and the High Court of the European Union will mention that private detectives are, before a trial, qualified witnesses.

A private detective, within Spanish law, refers to those private professionals who provide certain documentary (audiovisual evidence is the most commonly used), expert and testimonial evidence. Thanks to Spanish and European legislation, private detectives are the only professionals who can make use of hidden devices.

For lawyers, it is crucial to be able to have and possess hard evidence, as it enables them to show a fact that would otherwise have been impossible to prove.

Evidence: What value does it have in a trial?

In the following, we will clarify the value of evidence in a trial and how to ensure that it is useful for the trial.


We should remember that private detectives are professionals who have to undergo specific training in order to be able to exercise their profession. In addition, they must follow a rather strict legal framework for conducting private investigations. This implies that such investigations will have certain limits on the way in which evidence can be gathered, as well as delimiting the cases in which they can act. A trained private investigator will be useful to cover a wide range of investigations.

The evidence of a private professional can be quite useful for lawyers, as private investigations are objective, so that a lot of evidence is obtained through active observation, i.e. the work of private detectives. Along with the report/ratio, evidence can also be attached and submitted in different formats, e.g. pictures and videos confirming what the report/ratio says.

One of the most frequently asked questions by clients of a private detective is whether they can provide evidence to be presented in front of a judge, the answer is YES, THEY CAN, as long as they comply with the conditions stipulated by law.


Let us remember that when a private investigation is established, the detective will have to write a report as a result in order to be able to present it to his client. This document is the one that can be presented before a judge, as it is one of the means of proof that are allowed during a judicial process, according to what is dictated by the Law of Civil Procedure.

One could say that the report is the private detective’s testimony about the events of the past, which he himself has witnessed.. It recounts what has been seen and heard during the investigation in a sequential order. It is also important that the report should state who or what has been involved in the private investigation. The facts described in the report may be supported by other files, such as photographs, videos and other evidence obtained by the private investigator during the investigation.

Remember that for a report/part to be admitted as evidence, it must meet certain conditions. Some of these conditions are:

-The report must be drawn up by a qualified professional, i.e. he/she must be in possession of the Professional Identification Card (TIP), which is issued by the General Directorate of the Police.

If the private detective is not qualified to work as a private detective, he or she will be considered to be an intrusive employee, and the evidence provided will have no value in the eyes of a judge.

-All names of all persons involved in the investigation should appear in the report. The methods used to obtain the evidence should also be stated, and the methods used should not violate the fundamental rights of the persons under investigation.

If the object of the private investigation is internet scams, a computer expert must be present to testify in front of a judge during the trial.

-If the opposing party contests the private detective’s report, the private detective will have to go to court to rectify it in front of a judge during the trial.


After conducting a private investigation, the detective will provide litigation support, which means that the whole process will be within the legal framework, just as the experts are professionally prepared to speak and testify before a judge, and thus answer all questions that have a bearing on the previously drafted report.

The Supreme Court considers a private detective as a privileged witness, when he or she appears in court proceedings, as the latter is a private professional who has received the authorisation (TIP) to carry out investigations and, in addition, the evidence he or she presents in court will be supported by verifiable facts.


The presentation of evidence by a private detective in court is validated within the legal framework. Article 265 of the Civil Procedure Act recognises the report of private professionals as a specific and distinct form of witness evidence. In the aforementioned Law, but in article 380.0, it mentions textually that the recognition of the expert report in these cases, when they contain conclusions and observations based on technical, artistic or practical knowledge.

The Act also indicates and describes how an interrogation of a private detective should be carried out during the ratification of the report previously drawn up by the private detective. All questions shall relate to the facts as stated in the report. The private practitioner will appear before a judge only to speak about the facts that he or she saw or heard during the investigation, which are also reflected in the report. It will be impartial, just like the report, and this is what makes the difference to the other witnesses.


Like many other professions, private detectives must conform to what the law allows them to do, as there are limits that they must respect and if they do not do so, they may be sanctioned or fall into a criminal offence.

In the following we will explain what three basic conditions are necessary in order not to jeopardise the validity of a private detective’s evidence in court:

  • The private detective must be qualified.
  • The person who engages a private professional must have a legitimate interest for the investigation to be initiated.
  • At no time during the investigation may the fundamental rights of those involved in the investigation be violated.

It should be remembered that for a private detective to be authorised, he or she must have the TIP, which indicates that he or she is a professional and has the appropriate training to carry out investigations.

What a private detective can investigate

We will now show you what the profession of private detective can bring and what it can cover. We will also see what a private detective can investigate, in order to know the limits and possibilities of this service.


Private detectives help to find out the truth and to solve all the doubts that their clients may have. Likewise, these professionals can also obtain all the evidence necessary for the resolution of a legal case.

Their reports can be provided as documentary evidence. It should also be noted that, if necessary, private detectives can testify in court. It should not be forgotten that this profession is gaining ground in companies, as private detectives look after profit, performance and development in both companies and businesses.


We remind you that private detectives are covered by the Private Security Law and Regulations. These professionals are in the same league as other professionals in the same sector, such as security guards, security chiefs and directors, bodyguards, whether personal or otherwise, etc.

This law and the regulations governing these professionals are regulated by two very specific points:

  • Article 19 and 20 (Section VI); Regulating the functions of these professionals, the functions and activities that they may or may not carry out are indicated.
  • Articles 101 to 110 (Regulation Section VI).


We will now discuss the law that is currently in force. This Law was preceded by the Ministerial Order of 1981, in its article number 8, we can see how it states textually that private detectives cannot carry out private investigations into offences which can be prosecuted ex officio.

It is also true that such private practitioners sometimes encounter these prosecutable offences. When this happens, private detectives are obliged to make all information in the file immediately available to the police.

We emphasise that it is not possible to investigate matters that are not prosecutable ex officio, as long as they do not have a legitimate cause. They may not use technical means or materials that infringe the right to privacy, honor, image or make use of tools that may violate the protection of communications.


Among other things, the following are some of the things that private investigators can do after accepting a private investigation, whether the client is a natural or legal person;

  • These private professionals will be able to obtain and provide all information and evidence of the facts, as well as the conduct under investigation.
  • Private investigations of prosecutable offences may only be carried out when they are commissioned in a legitimate way by criminal proceedings.
  • Among other things, surveillance can be carried out in hotels, events, exhibitions and similar areas.

Limits of private detectives

A security and investigation expert must guarantee and respect the rights of both his clients and the persons under investigation, which is why the right to privacy must not be violated at any time during surveillance.


In general terms we could say that privacy or intimacy is the area of a person’s personal life that takes place in private spaces, and that he or she has the right to control, defend and protect in case of intrusion.

On the other hand, the right to privacy could be defined as the defence of individuals through the prohibition of public disclosure of private information related to work, religion, personal life, politics, etc.

Within the fundamental right of the person we can find the right to be able to enjoy a personal and private sphere to build a family and personal life completely free, except from the knowledge or interventions of third parties.


Limits of private detectives 2
  • Appropriation of image or name. Private investigators should avoid impersonating someone else, because if a person or organisation uses your image or your name for profit without your consent, they can make a legal claim.
  • Public disclosure of private information. A very common example is the theft of private information via WhatsApp. In order for a person who has suffered from this to initiate legal proceedings, it is important that the information disclosed is completely truthful, not in the public interest, and is considered offensive. Emphasise that what we have just read is not about defamation.
  • Image distortion: When we talk about image distortion it is very similar to defamation.


Limits of private detectives 3

Private detectives are regulated by a series of laws that protect the legitimate rights of their clients and of the persons under investigation, although they may collect evidence, follow people, search for information related to the persons involved in a file and other tasks.

These private professionals must act in accordance with the provisions of Law 5/2015 on Private Security. In this law, it states that the private investigator himself is primarily responsible for preventing the rights of the persons under investigation from being violated.

It should be emphasised that the services and actions that a private detective can carry out may never infringe the rights referred to in the Spanish Constitution, specifically in article 18. This article deals with the public freedoms of individuals and their fundamental rights.

Some aspects of it could be; the guarantee of the right to honour and personal and family privacy and even the right to one’s own image, and/or the protection of the home, in short, it could be said that no private investigation can be carried out and no entry can be made into a private home without the consent of the owner of the home, unless there is a warrant signed by a judge.


Limits of private detectives 4

The right to personal privacy is one of the most important rights under the Private Security Law. This right should be taken into account both in the gathering of evidence and at every stage of the private investigation process.

According to the legislation, private detectives must comply with certain rules or limitations, which are shown below:

  • In order to prove the legitimacy of the private service, the interest of the private service in a case must be reflected in the private contracting and investigation file itself.
  • Enquiries and the gathering of information and evidence relating to prosecutable offences may only be carried out at the request of the legitimate client in the context of criminal proceedings.
  • With the exception of all activities that take place in private homes or private areas, all activities related to financial, economic, work, personal, family or social and business life are accepted if such activities take place in public places.


Limits of private detectives 5

With the exception of data that may be linked to a possible crime or to the persons involved, any information that does not relate to the purpose of the file will be discarded, so when private detectives carry out the appropriate enquiries and evidence gathering they should always focus on the purpose of the private investigation.

It should be noted that private professionals who violate the right to privacy of the person under investigation are brought before a judge and penalised by law. If you are considering hiring any of the services offered by a private detective, make sure that he or she respects the privacy rights of the persons involved in a case.

Everything you need to know about the work of a private detective


Over the years, the profession has evolved by leaps and bounds, and today’s private detectives are becoming more and more qualified. To become a member of this group you need a university degree and accreditation from the Ministry of the Interior.

It should be noted that Spanish training is the most comprehensive in the European Union. Spanish private detectives are the best trained in Europe, because they are the only ones in Europe who need a university degree and a postgraduate degree in private investigation to obtain such a licence.

A private detective is basically a support for private or legal investigations, and a large part of his work consists of office work, as the person being investigated must first be traced via the internet.

The reports resulting from such private investigations serve as evidence in trials and cases, making private detectives privileged witnesses.


Thanks to social media and mobile technology, it is becoming easier and easier to investigate someone, making it quicker and easier for a private detective to do their job. We are all visible through our mobiles and every internet connection, we leave easily traceable traces, even the smallest detail is useful to a private investigator, from the last Whatsapp connection to our Whatsapp profile picture or even a comment from a friend on any social network. Thanks to all this and a few other things, people have become easier to control than ever before and without the need to break any laws.

Nowadays, it is very difficult to stop being part of applications and social networks, such as Facebook, Twitter or Instagram. Private detectives take advantage of this, because thanks to the various social networks and mobile phones, they achieve half of their targets effortlessly.

Beyond technology, private detectives still need the investigation/surveillance on the street, as it has always been done. Once someone is located through social media or a mobile phone, they need to be tracked, monitored and recorded.

With the rise of private detective work thanks to social networks, the work of the computer expert has also developed. The function of the latter consists of analysing computer elements in search of data that may constitute evidence or evidence useful for the legal dispute to which he/she has been assigned.


All private investigations carried out by a private detective must have a legitimate interest, according to a court. In a nutshell, this means that you can’t hire these research services just because one person dislikes another or just because they want to ridicule them. Each investigation should be recorded and the work should be monitored from time to time by a public body, namely the police. As a result, the work of a private detective is highly supervised and organised.

Regulations on private investigation

Before agreeing to start a private investigation, private investigators must carry out a number of checks.

The Private Security Law establishes guidelines that govern the activity of private detective firms throughout the national territory. There are also clear rules on the competences of private detectives, consisting of scopes and prohibitions.

Some of the most prominent are:

1- Private detectives are obliged to give evidence, present reports or results of investigations before a court, if required by a competent judge.

2- Private detectives must be registered in the National Register of Private Security.

3- There must be a contract for investigative services, which must be signed by the private detective and the applicant. This contract must also be communicated to the Ministry of the Interior or to the relevant Community body.

4- Private detectives who do not have a licence issued by the Ministry of the Interior will not be legally authorised to carry out any type of private investigation.

5- Private detectives cannot investigate facts related to prosecutable offences, and are obliged to report the commission of an offence to the competent authority.

Private Security Act 5/2014

The private detective profession is regulated according to the Private Security Law 5/2014.

Article number 48.1:

“The private investigation services provided by private detectives shall consist of carrying out the necessary investigations to obtain and provide, on behalf of legitimate third parties, information and evidence on private conduct or events related to the following aspects:

1.- Those relating to the economic, employment, commercial, financial and, in general, personal, family or social life, except for that which takes place in homes or reserved places.

2.- Obtaining information aimed at guaranteeing the normal development of activities that take place at fairs, hotels, exhibitions, shows, events, conventions, large shopping centres, public premises with a large number of visitors or similar areas.

3.- The carrying out of investigations and obtaining of information and evidence relating to offenses that can only be prosecuted at the request of a party on behalf of the parties entitled to participate in criminal proceedings”.