A measure conceived as exceptional becomes routine, revealing how prolonged detention undermines the presumption of innocence and distorts the criminal process.
by Alessandro Amicarelli — Preventive detention occupies a precise place in international law. It is conceived as an exceptional measure, justified only when strictly necessary, and surrounded by safeguards that protect the presumption of innocence. The International Covenant on Civil and Political Rights affirms that deprivation of liberty before trial must be used sparingly and only when alternatives are not available. The United Nations Human Rights Committee has repeatedly insisted that courts must examine whether less intrusive measures can achieve the same protective purpose.
Duration is central to this analysis. An exceptional measure cannot become prolonged without losing its character. Judicial control must be effective, and judges must verify whether the reasons prosecutors invoke remain valid over time. The presumption of innocence is not a decorative principle. It requires that the accused be treated as a person not convicted and that their liberty not be curtailed for extended periods without compelling justification.
I have examined the cases of Konstantin Rudnev and of the police officers accused of the murder of Franco Casco in Argentina. While I believe that Rudnev is innocent, I do not take a position on the Franco Casco murder, a complicated case I have not studied enough. However, I do take a position on pre-trial detention in the Franco Casco case. As with Rudnev, pre-trial detention seems to be applied in a way inconsistent with international law. To explain this point, I first need to outline how the legal principle of the exceptional character of pre-trial detention has been interpreted internationally. My method here is to rely on the case law of the European Court of Human Rights, whose decisions are increasingly cited outside Europe, as well as reliable interpretations of international principles.
Protest by the defendants’ relatives in the Franco Casco case. Screenshot.
The European Court of Human Rights has built a substantial body of case law on preventive detention, and its judgments offer a detailed map of the limits that democratic systems must respect. The Court has held that detention before trial must be time-limited and justified by concrete, individualized reasons. It has examined cases where prosecutors relied on generic formulas and found violations when courts failed to scrutinize them. The Court has also insisted that time changes the legal landscape. A reason that may justify detention at the beginning of an investigation may lose weight as months pass. In several judgments, the Court has condemned prolonged detention when investigative steps were slow, or authorities did not act diligently. It has also examined cases where authorities did not consider alternatives to imprisonment, and it has found violations when courts did not explore measures such as bail, reporting obligations, or restrictions on movement.
In the landmark case Letellier v. France (26 June 1991), the Court held that preventive detention must remain exceptional and cannot be justified by simply citing the gravity of the charges. Mrs. Letellier was accused of having paid two killers who murdered her husband. The charge was extremely serious. Yet, even in this case, the European Court held that pretrial detention should be limited to a reasonable time and, when the defendant is detained, the investigation should proceed swiftly. France’s arguments that it was necessary to prevent her from bringing pressure to bear on witnesses, that there was a risk of her absconding, that court supervision was insufficient, and that her release would gravely disturb public order were all dismissed.
The Letellier decision has been quoted in many subsequent cases because it establishes the principle that the prohibition against keeping defendants in pretrial detention for a time that exceeds reasonable limits, particularly when the investigation does not proceed quickly enough, is absolute and cannot be derogated from because of the gravity of the crime or the risk that the defendant may influence witnesses.
The European Court of Human Rights established another important principle in Clooth v. Belgium (12 December 1991). The Court ruled that pretrial detention cannot be prolonged when investigative authorities fail to act with diligence. In this case too, the crime was of exceptional gravity, the murder of a young girl. In view of the circumstances, a longer-than-usual pretrial detention might have been justified, the Court said. However, the European judges noted that the prosecution conducted its investigation in a cavalier and questionable way. This made the length of the pretrial detention, even in a case of murder, unjustified.
Together with Letellier and Clooth as classic early cases, Ilijkov v. Bulgaria (26 July 2001) is often added because it includes a detailed explanation of another principle: whether pretrial detention is allowed or prohibited also depends on the effectiveness, fairness, and easy availability of remedies and appeals for the defendant. This was lacking in Bulgaria.
We can thus conclude that early ECHR judgments, correctly applying international law, established three fundamental principles about pretrial detention as a measure that should remain exceptional. It should not exceed reasonable time limits, even in the most serious cases. It should be accompanied by an effort to advance the investigation without undue delays. It should also be applied in a context where remedies such as appeals and recourse to a Supreme Court are easily available to the defendant, decided timely, and examined fairly.
These principles are now well established and repeated in dozens of ECHR decisions. However, I still want to quote two cases from this year because they concern Ukraine and reach opposite conclusions, which is precisely why they are interesting.
In Kolesnyk and Smelnytskyy v. Ukraine (23 July 2026), the Court admitted an exception to the Letellier principle when a country is in a situation of war. In this case, when a defendant is investigated for crimes such as high treason and espionage, what would otherwise be prohibited pretrial detention may become legitimate. But even in this special case, the principle that pretrial detention is an exceptional remedy remains valid.
In another 2026 case, Derevyanko and Tarasova v. Ukraine, decided on the same day as Kolesnyk, the ECHR stated that even in cases of espionage in a situation of war, the state’s interest justifying pre-trial detention should be balanced against the defendants’ human rights. Unlike in Kolesnyk, the ECHR found against Ukraine, considering that the prosecutors’ handling of the evidence and assessment of the risk of escape of the defendants in this case was not persuasive.
The ECHR’s evaluation of pretrial detention in war-torn Ukraine thus confirms that even exceptions to the general principles in cases of war and espionage are not absolute. What is absolute is the principle that pretrial detention should be considered and treated as an exceptional remedy irrespective of the gravity of the crime.
The European Court of Human Rights. Credits.
Some European countries have incorporated these principles into their domestic systems with considerable precision. In Germany, preventive detention is subject to strict time limits, and courts must justify any extension with detailed reasoning. In France, pretrial detention is capped at two years with very limited exceptions, and judges must review the measure at regular intervals. These systems differ in their details, yet they share a common foundation. Preventive detention is exceptional, and its use must be justified at every stage.
Argentina presents a different picture. Preventive detention is widely used, and its exceptional character has been eroded. The problem is not limited to isolated excesses. It has become an established working method. Preventive detention is frequently applied at the preliminary investigation stage, and detention periods are imposed that are difficult to regard as proportionate. Accused persons may remain in prison for years while inquiries continue. The Franco Casco case illustrates the scale of the problem. A police commissioner and several colleagues spent six years in preventive detention. A basic procedural question follows. What required six years of investigation? The file’s complexity and the volume of investigative work do not explain such a timeframe.
Argentine national law itself points in a different direction. Article 210 of the Code of Criminal Procedure constructs a ladder of coercive measures and places prison-based preventive detention at the end. The Supreme Court has stated that preventive detention may not be applied arbitrarily or as routine. In practice, these constraints are not consistently observed. Official figures confirm the scale of the problem. At the end of 2024, 45,305 people were deprived of liberty without a final sentence, representing 37.3 percent of all prisoners. The source is the report of the National Committee for the Prevention of Torture. A share that large means an exceptional measure has become a working tool. In theory, its function is precautionary, but prolonged detention creates conditions in which pressure can be exerted on the accused to obtain confessions or negotiated admissions of guilt.
Prosecutorial practice contributes significantly to the problem. It is not limited to extending time limits. It also involves pressure on the accused through lengthy preventive detention and the prospect of years in custody before any judgment. Pressure is also exerted on complainants through intimidation and restrictions on the right to a defense.
The Konstantin Rudnev case illustrates the pace and quality of the investigation. After a year and a half, basic investigative steps have only recently begun. None of the accused has been interrogated. Testing of medicines seized at the time of arrest showed that they contained no narcotic substances. Investigators examined items and medicines seized in house searches more than a year after the investigation opened. Telephone examinations have proceeded extremely slowly. The contents of seized bags consist mainly of clothing, shoes, personal effects, and food. No accounting, financial, or other documentation explains such prolonged expert examination. The question arises. What has been under examination for a year and a half?
In both the Rudnev and the Franco Casco case, handled by the same prosecutor, Fernando Arrigo, the three tests of the European Court of Human Rights would lead to the conclusion that a long pretrial detention is not justified. The Letellier test: pretrial detention is too long. The Clooth test: the prosecutor and his team are exceptionally slow in advancing the investigation. And the Ilijkov test: remedies such as appeals and recourses do not seem to be easily available and decided in a timely and fair manner.
The conclusion must be carefully formulated. If the present regime of preventive detention remains in force, it is difficult to say that Argentina meets the standards of a democratic and humane criminal process. The presumption of innocence, human rights, and the declared humanitarian character of the procedure exist formally, and they lose their meaning when a person spends years in prison before any sentence. The suggestion that follows is modest and legal rather than political. Argentina should align the application of preventive detention with international law and with its own Constitutional principles.
Konstantin Rudnev in happier times.
I would add that humanitarian factors in pretrial detention should also be considered. Konstantin Rudnev’s health situation has been made much worse by detention. As a moving video in the Casco case shows, years of uncertainty, distance, and institutional hostility reshaped the daily lives of the defendants’ families in ways no legal system should ignore. Children who once expected their parents to return from work began to associate the word visit with metal detectors, searches, and the fear of being separated again. Several minors developed bronchospasms, vomiting, diarrhea, and regressions in their development. Doctors explained that these symptoms were emotional. The children were stripped during security checks, asked to remove their shoes, and subjected to procedures they could not understand. They traveled long distances only to return home sick and silent. Some stopped speaking, others wet the bed, others lost the ability to walk and reverted to crawling. A child with developmental delays began to regress after each visit, and another, who could not express himself verbally, reacted with fever and vomiting whenever they realized that a trip to the prison was approaching. These experiences leave marks that endure long after the legal case has ended.
The adults carried their own burdens. Wives traveled hundreds of kilometers to see their husbands for a few hours, endured invasive searches, and tried to remain calm so that the visit would not be interrupted. One woman was undergoing cancer treatment while raising her children alone. Another lost the vision in one eye and later required heart surgery, conditions that doctors linked to prolonged emotional stress. Families described how they had to adapt to the routines of the penal system, how food brought from home was pierced with knives used moments earlier to open bags of detergent, how infants had their nappies removed during inspections, and how every departure from the visiting room was a moment of anguish. Older siblings became de facto guardians, left school to care for younger children, and tried to shield them from the truth. A ten-year-old girl explained that she had learned to suppress tears during visits so she would not upset her mother. Another child was bullied at school because classmates said he had no parents.
These accounts confirm that preventive detention is not a neutral procedural measure. It is a force that reshapes entire families, imposes suffering that no judicial decision can repair, and creates a legacy of trauma that persists long after the courts have spoken.
Preventive detention must be exceptional. When it becomes routine, it ceases to be lawful. The Argentine system has reached a stage where this measure is used in ways that contradict international standards and diverge from the example set by the European Court of Human Rights. The accused, their families, and the credibility of the justice system bear the consequences. What is needed is reform that restores the exceptional character of preventive detention, strengthens the rule of law, and aligns Argentina with the principles it has undertaken to respect.
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