First and foremost, it can be stated that a solid understanding of precautionary measures, their effects and requirements, is a distinguishing factor for professionals working in the defense of rights in criminal matters.
Based on the prestige associated with this topic, this article aims to guide the reader in a simple way to understand the concept of precautionary measures.

Changes in the application of precautionary measures
First, there were changes in the application of precautionary measures brought about by Law 12.403/11.
Prior to this, pretrial detention was the rule, while the granting of provisional release or even precautionary measures other than imprisonment were exceptions.
So, from the moment the law was published, there was a reversal of circumstances: now, pretrial detention should only occur exceptionally.
According to article 282, § 6 of the Code of Criminal Procedure:
"Preventive detention will only be ordered when it is not possible to replace it with another precautionary measure, in accordance with article 319 of this Code."
What exactly are precautionary measures?
In summary, precautionary measures are tools applied before or during the process and are focused on preserving the criminal prosecution.
The impact of this is to ensure the formation of evidence regarding the authorship and materiality of the crime.
Furthermore, the name is quite suggestive: they are measures that, as a precaution, are determined to ensure :
- that the person under investigation, during the course of the investigation;
- or the accused, during the course of the proceedings;
- do not interfere with law enforcement, do not hinder the production of evidence and Do not repeat criminal practices.
What are the types of precautionary measures?
In short, precautionary measures can take the form of precautionary detentions , including preventive detention and temporary detention ; or measures other than imprisonment , which, instead of restricting freedom/movement, restrict other rights of the individual.
Similarly, Article 319 of the Code of Criminal Procedure states that the following are precautionary measures other than imprisonment:
"I - periodic appearance in court, within the time and under the conditions set by the judge, to report and justify activities;
II – prohibition of access to or attendance at certain places when, due to circumstances related to the fact, the suspect or accused must remain away from these places to avoid the risk of new offenses;
III – prohibition against maintaining contact with a specific person when, due to circumstances related to the fact, the suspect or accused should remain distant from that person;
IV – prohibition from leaving the district when remaining there is convenient or necessary for the investigation or proceedings;
V – house arrest during nighttime hours and on days off when the investigated or accused person has a fixed residence and job;
VI – suspension from exercising a public function or an activity of an economic or financial nature when there is a justified fear of its use for the commission of criminal offenses;
VII – provisional detention of the accused in cases of crimes committed with violence or serious threat, when the experts conclude that he is not criminally responsible or partially criminally responsible (article 26 of the Penal Code) and there is a risk of recidivism;
VIII – bail, in offenses that allow it, to ensure appearance at procedural acts, prevent obstruction of its progress, or in case of unjustified resistance to a court order;
IX – electronic monitoring.
Pretrial detentions: how to differentiate them?
Firstly, temporary detention and preventive detention differ in the timing of their application.
Temporary detention can occur during the police investigation phase, while preventive detention can occur at any stage, whether investigative or procedural.
In addition, the qualities listed below are scored.
Temporary detention
- Regulated by law 7.960/89;
- When it is essential for the investigations, the subject does not have a fixed residence or does not provide sufficient information about their identity, and there are well-founded reasons to believe they are the perpetrator or involved;
- It has a duration of 5 (five) days, and may be extended for an equal period in cases of extreme and proven necessity;
- It occurs during the police investigation phase (pre-trial).
Preventive detention
- Prediction within Code of Criminal Procedure, articles 312 and 313;
- It requires evidence of authorship and materiality of the crime, in addition to the danger posed by the individual's state of freedom.
- It does not have a legally pre-defined duration period; what the law requires is that the reasons that led to its application be re-evaluated every 90 (ninety) days;
- It occurs in any phasewhether investigative or procedural, provided that the requirements set forth by law are met.
What is the main purpose of pretrial detention?
Primarily, the objective is to ensure, in a more rigorous manner, the success of the criminal investigation, as well as to maintain public and economic order during the criminal proceedings , given the impossibility of applying less restrictive precautionary measures.
In the case of preventive detention, the authority should only order it if the requirements of article 312 of the Code of Criminal Procedure are met.
Therefore, this requires evidence of authorship and materiality of the crime, in addition to the danger generated by the individual's state of freedom.
Regarding temporary detention, since its application is directly conditioned on the investigation phase, Law 7.960/89 , in its very first article, determines that it will be applicable when:
"I - essential for the investigations of the police inquiry;
II – The nominee does not have a fixed residence or does not provide the necessary information to clarify their identity;
III – if there are well-founded reasons, according to any evidence admitted under criminal law, of the suspect's authorship or participation in certain crimes.

Final considerations regarding precautionary measures.
Therefore, it can be said that after Law 12.403/11, precautionary measures gained a new perspective within the criminal process, especially with regard to the legislator's concern in safeguarding fundamental rights.
Conversely, what hasn't changed is that precautionary measures continue to act as tools aimed at guaranteeing order and security in criminal investigations and the criminal process itself.
That is why the professional who truly understands what the law stipulates regarding the application of precautionary measures acts, first and foremost, as a monitor of any and all non-compliance that leads to the erroneous application of these measures.
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