Defensive investigations allow you to search for elements useful to the defense without limiting yourself to waiting for the conclusion of the public prosecutor's investigations. If you are a suspect or accused person, you may wonder who has the power to contact a person with knowledge of the facts, acquire a document, examine a place, or preserve a technical trace before it disappears.
In this guide I want to clarify what the defense can do, what rules it must follow, and why an informally gathered statement is not equivalent to a documented act. We will also see when the intervention of the judge is necessary, what happens if a person refuses to answer, and in what way the results can be presented in the proceedings. The central point is to distinguish a legitimate and usable search from an activity lacking the necessary forms.
What defensive investigations are
The defense can search for favorable evidence starting from the conferral of the professional assignment, provided this results from a written act. Article 327-bis of the code of criminal procedure allows defense counsel to carry out investigations to identify elements in favor of the client, according to the forms provided by articles 391-bis and following. The discipline was introduced by law no. 397 of December 7, 2000.
This is not a parallel public investigation. Defense counsel does not have the coercive powers of the public prosecutor and the judicial police: they cannot impose a search, intercept communications, or freely compel a person to answer. The Constitutional Court itself has noted that the investigative means of the public party remain broader than those of the defense, while acknowledging the role of defensive investigations in the right to defend oneself by proving, as emerges from Constitutional Court judgment no. 184 of 2009.
Usefulness depends on the specific question. A person present at the scene can clarify a sequence of facts; a document can disprove a date; a technical survey can show that a reconstruction is not compatible with the state of the places. The investigation is not meant to construct an artificial version, but to verify whether lawful, relevant, and verifiable elements exist that the public investigation did not acquire or interpreted differently.
Who can carry them out and when they can begin
Defense counsel directs the investigative activity. Upon their instruction, a substitute, authorized private investigators, and, when specific expertise is needed, technical consultants can operate. The roles are not interchangeable: an investigator can search for people, reconstruct lawful movements, and conduct informal interviews, while a computer, medical, or ballistic evaluation requires adequate technical knowledge.
Investigations can continue in various phases of the proceedings, not only during preliminary investigations. Article 327-bis admits them in every state and degree, in criminal enforcement, and to promote a review proceeding. However, the purpose, the concretely useful acts, and the rules through which the result can be brought before the judge change.
Preventive activity is also possible. Article 391-nonies allows it to be carried out in the event that criminal proceedings are instituted, on the basis of a specific mandate with authenticated signature, containing the appointment of defense counsel and the indication of the facts concerned. Acts that require the authorization or intervention of the judicial authority remain excluded. Title VI-bis of the code of criminal procedure introduced by law no. 397 of 2000 governs the prerequisites and forms of individual acts.
How information is gathered from individuals
The informal interview is not a record. Defense counsel, the substitute, the authorized investigator, or the consultant can speak with a person able to report useful circumstances. In this mode, the news is not documented: the interview serves to understand what the person knows and whether facts worthy of formal acquisition exist.
The formal statement follows stricter rules. Defense counsel or their substitute can receive a written statement or take verbalized information according to article 391-ter. First, they must explain their qualification, the purpose of the meeting, the form of the documentation, the right to remain silent, and the responsibilities connected to false statements. They must also verify whether the person is a suspect or accused in the same proceedings or in connected proceedings.
The person may refuse to answer. Defense counsel cannot turn the meeting into a coercive interrogation nor suggest the content of statements. If the person exercises the right to remain silent, article 391-bis allows, under certain conditions, asking the public prosecutor to hear them; the public prosecutor sets the hearing within seven days of the request. Alternatively, the taking of testimony or examination through evidentiary hearing may be requested. These tools do not operate in the same way for persons suspected or accused in connected or related proceedings.
For a co-suspect, their defense counsel is needed. When wishing to speak with a person suspected or accused in the same proceedings, in connected proceedings, or for a related offense, their defense counsel must be notified at least twenty-four hours in advance and must be present. For a detained person, a specific authorization from the competent judicial authority is also required.
Self-incriminating statements require interruption. If a person initially heard as an informed subject reports facts from which evidence of a crime emerges against themselves, the gathering of information must stop. Previous statements cannot be used against them. Violation of the guarantees provided by article 391-bis can render the gathered information unusable and entail disciplinary consequences.
Documents, places, and technical investigations
Public documents can be requested from the administration that formed them or permanently holds them. Article 391-quater recognizes defense counsel's faculty to request them for defensive investigations and to extract copies at their own expense. Refusal does not authorize autonomous acquisition: the procedural remedies referred to in the rule must be used.
Access to places can fix elements destined to change. Defense counsel, the substitute, and assistants can observe the state of places and things, describe them, and perform graphic, photographic, audiovisual, or technical surveys. The documentation must identify the place, date, persons involved, what was observed, and the surveys performed. An isolated photograph, lacking context and provenance, offers lower guarantees than correctly documented activity.
In private places, consent matters. If the person who disposes of the place does not allow entry, access must be authorized by the judge with a decree establishing the modalities. For homes and appurtenances, the rule is even more restrictive: access is permitted only when it is necessary to ascertain traces or other material effects of the crime. Defensive investigation, therefore, does not justify arbitrary intrusions.
Non-repeatable acts require particular caution. An assessment is non-repeatable when its object is destined to change or the operation alters its state. In the case of a non-repeatable technical assessment, article 391-decies requires notifying the public prosecutor without delay so that they may exercise the faculties provided by law. Omitting necessary adversarial proceedings can compromise the use of the result.
Digital data must also be contextualized. A message, video, or file can be relevant, but simple printing or photographing of the screen does not always prove who produced the content, whether it is complete, or whether it underwent modifications. When these aspects are contested, the preservation of the device, original data, and technical information can become decisive.
How results enter the proceedings
The result does not automatically become evidence. A distinction must be made between the search for the element, its correct documentation, filing in the proceedings, and the regime with which it can be used. An undocumented interview, for example, cannot be presented as if it were a record; however, it can guide the subsequent request for a formal statement or testimony.
Favorable elements can be presented to the public prosecutor and, in cases provided by article 391-octies, directly to the judge. During preliminary investigations and the preliminary hearing, the filed documentation forms the defense counsel dossier. The choice of timing must consider the awaited decision: a precautionary request, possible dismissal, the preliminary hearing, or a trial strategy pose different needs.
The judge retains the power of evaluation. Defensive provenance does not make an element irrelevant, nor does it attribute unquestionable effectiveness to it. Legality of acquisition, relevance, reliability, possibility of comparison with other acts, and specific rules of the rite matter. Constitutional Court judgment no. 117 of 2011 recalls, in the context of the preliminary hearing, that the parties can address productions and the judge decides on their admission.
Statements and material acts follow different regimes. Article 391-decies recalls specific modalities of use for statements contained in the defense counsel dossier. Documentation of non-repeatable acts performed during access to places can instead flow into the trial dossier in cases established by the rule. For this reason, it is not enough to gather useful information; one must choose from the beginning a form consistent with possible procedural use.
What activity can be useful to the defense
The first choice concerns the fact to be clarified. If the controversial point is what a person saw, a declarative activity may be useful. If it concerns a date or a communication, the original document may be more reliable than memory. If it depends on the material compatibility of a reconstruction, access to places or a technical consultation can gain relevance.
Promptness and regularity must proceed together. Waiting can lead to the loss of recordings, traces, or precise memories; acting without respecting forms can make what has been gathered useless. It is therefore important to avoid improvised contacts with witnesses, unauthorized access, alterations of original files, and initiatives that could influence a person or confuse their memories.
The investigation must confront the concrete accusation. Gathering a lot of material is not equivalent to strengthening the defense. An element is useful when it affects a genuinely controversial passage: it identifies another person, refutes a temporal placement, offers a verifiable alternative explanation, or shows a technical limitation of the accusatory reconstruction. Even an unfavorable result can avoid founding the strategy on a hypothesis refuted by the facts.
Frequently asked questions
Can a private investigator gather testimony?
They can conduct an undocumented interview if authorized and instructed by defense counsel, but they cannot alone receive the written statement or take the verbalized information provided by article 391-bis, paragraph 2. These formal activities fall to defense counsel or their substitute and must respect warnings and documentation modalities established by law.
Is a person contacted by the defense obliged to answer?
No, they may not answer and may refuse to make a statement. If conditions are met, defense counsel can ask that they be heard by the public prosecutor or request an evidentiary hearing. However, it is not possible to bypass the guarantees provided for co-suspects, accused persons in related proceedings, or persons from whose words evidence against themselves emerges.
Can defensive investigations begin before proceedings start?
Yes, preventive activity is admitted on the basis of the specific mandate governed by article 391-nonies. The mandate must have an authenticated signature, appoint defense counsel, and indicate the facts to which it refers. Before proceedings are instituted, acts requiring the authorization or intervention of the judicial authority cannot be performed.
Must the judge accept everything the defense gathers?
No, automatic entry does not exist. The judge verifies relevance, legality of acquisition, and utilization rules applicable in the specific procedural phase. An informal interview, a verbalized statement, a document, and a non-repeatable assessment have different natures and cannot be presented or employed as if they produced the same effects.
Can the defense enter a private place to take photographs?
The consent of the person disposing of it is needed or, when the law permits, motivated judicial authorization. In homes and appurtenances, access is permitted only if necessary to ascertain traces or material effects of the crime. Photos or surveys obtained through arbitrary entry can create serious problems of legitimacy and use.
Understanding if you need to act immediately
Time matters when an element can disappear, but haste must not compromise guarantees. To prepare an initial comparison, the act received from the authority, an essential chronology, the indication of relevant persons or places, and original supports of available data are useful. If you want to understand what activity is consistent with your procedural position, you can contact me.