The Mexican criminal law system


Despite our best efforts, the Government of Canada cannot guarantee that the information in this publication is accurate, complete or that it is up to date at all times. Although care has been taken in preparing this information, it is provided on an "as is" basis without warranty of any kind, express or implied. The Government of Canada assumes no responsibility or liability of any kind and shall not be liable for any damages in connection to the information provided. This publication is not intended to provide legal or other advice and should not be relied upon in that regard. The reader is encouraged to retain a lawyer, if arrested or detained, and to supplement this information with independent research and professional advice.


This document is intended to give you basic information on how the Mexican criminal law system functions. It is not a substitute for legal advice, which can only be provided by a lawyer qualified to practice in Mexico. It should also be read in conjunction with the brochure A Guide for Canadians Imprisoned Abroad.

If you break the laws of another country, you are subject to the judicial system of that country. Being a foreigner or not knowing the local laws is not an excuse. Global Affairs Canada can neither protect you from the consequences of your actions nor override the decisions of local authorities. The Mexican and Canadian criminal law systems are significantly different. This can increase the stress and practical problems arising from arrest and imprisonment in Mexico.

The Government of Canada will make every effort to ensure you receive equitable treatment under the local criminal justice system. It will seek to ensure you are not penalized for being a foreigner and that you are neither discriminated against nor denied justice because you are Canadian. It cannot, however, seek preferential treatment for you or try to exempt you from the due process of local law. Just as a foreign government cannot interfere in Canada’s judicial process, the Government of Canada cannot interfere in the judicial affairs of another country.

For further information on the services consular officials can and cannot provide, please consult the brochure A Guide for Canadians Imprisoned Abroad.

Mexico initiated a comprehensive reform of its judicial system in 2008. Due to differing paces of implementation among the various jurisdictions (state and federal), Mexico currently has different criminal justice systems in effect both within and across its 33 judicial jurisdictions. Full implementation of these reforms is expected to take several years, and the official deadline across all jurisdictions is in 2016.  

Your choice of legal representation in Mexico can be critically important and should be made with care. For further information, please consult the section on selecting a lawyer in the brochure A Guide for Canadians Imprisoned Abroad.

Arrest and detention 

In the Mexican criminal law system, there are state and federal offenses. Offenses related to organized crime, drug trafficking, taxes, and customs operations are normally federal offenses. An arrest can be made by local, state or federal police. If you are accused of committing a crime, you will be turned over to the federal police if your arrest is related to a federal crime.

Under Mexican law, you may be arrested and detained when the police believe there is sufficient evidence against you to justify detention and/or criminal charges. In practice, you may be detained until a verdict is issued. This may take a long time.

Under the Mexican Constitution, you are entitled to have an interpreter appointed by the Mexican government to help during questioning by judicial authorities if you do not understand Spanish. You are also entitled to an oral translation of any written statement you are required to sign. The skills of Spanish-English interpreters can vary greatly, and skilled Spanish-French interpreters are not as easily available.

Under Mexican law, you do not have to give incriminating testimony or answer incriminating questions. You should, however, answer questions related to identity, age, address, occupation, citizenship and other non-incriminating personal information. When you are initially held by the police, you may feel pressured to speak before having the opportunity to communicate with a lawyer. You do not have to yield to such pressure and you have the right to remain silent. You also may insist on speaking with a lawyer.

Your rights under the Vienna Convention on Consular Relations

If you are detained or arrested abroad and wish to have Canadian consular officials notified, you should communicate that request clearly to the Mexican authorities. The Mexican authorities have an obligation, under the Vienna Convention on Consular Relations, to advise you of your right of access to a consular representative. They are not, however, obliged to inform a Canadian consular post of your detention or arrest, unless you ask them to do so.

Under the Convention, Mexican authorities are also required to forward to a Canadian consular post any communication you address to the consular post. This is in accordance with your rights to communicate with, and have access to, a consular official. For example, if you write a letter to the Embassy of Canada or another Canadian consular office in Mexico, that letter must be delivered. These rights must be exercised in conformity with the laws and regulations of Mexico.

If you choose to talk to Canadian consular officials, any information you give them will remain confidential, subject to the provisions of Canada’s Privacy Act. It will not normally be passed on to anyone other than the consular officials concerned with your case without your permission. However, under the Privacy Act, personal information may be disclosed in certain circumstances, such as in cases where disclosure would clearly benefit you, where the public interest in disclosure clearly outweighs any invasion of your privacy, or pursuant to a court order. Please consult the Consular Services Privacy Notice Statement for more details.

At your meeting with a consular official, please inform him/her if the Mexican authorities did not inform you of your right to request that Canadian officials be advised of your arrest or detention, or at any time denied you the right to communicate with, or have access to, a Canadian consular official.

The preliminary investigation

Following the arrest, the police make an initial determination as to whether a crime has occurred and whether there are grounds to believe that you committed the crime. At this point, the police will take you before the Ministerio Público, the government agency responsible for prosecutions.

The Ministerio Público conducts a preliminary investigation to determine whether the case should be prosecuted. If the Ministerio Público decides to proceed with the trial, the case will be turned over to a judge. The Ministerio Público generally has 48 hours from the time of receiving the case to make this determination. If it does not make a determination within 48 hours, you will normally be released.You should proactively monitor the progress of your case and inform your lawyer if you believe that the timeframe for the preliminary investigation by the Ministerio Público has not been respected.

The 48-hour period may be extended. In cases involving organized crime or when it is believed you could disappear before the preliminary investigation is completed, the Ministerio Público can request preventive detention (arraigo) from a criminal judge. Being a Canadian does not exempt you from preventive detention, even if you have immediate travel plans to return to Canada. Canadian citizens have been placed in preventive detention. When this occurs, you are placed either under house arrest or in a special detention centre. Detention during this investigation period can extend for several weeks, and in practice may extend for longer, depending on the jurisdiction and the crime. It should not be confused with further detention during the trial (see below). You should ask your lawyer about the length of detention that may apply to your circumstances.

If the Ministerio Público determines that a crime has taken place and it should be prosecuted, you will appear before a judge. This is the first time you will have access to a judge. The judge then has 72 hours to decide whether you should be tried or released. If the judge decides that a trial should take place, the judge will confirm the accusation with a detention order (auto de formal prisión). In some cases, the 72-hour period may be extended. The trial officially begins when the detention order is issued. If you are not already in detention, an arrest warrant (orden de aprehensión) is issued by the judge.

Bail is not common in the Mexican legal system. The right to request bail does exist under both the older inquisitorial and new adversarial systems (see below). It may not be available for people accused of serious or violent crimes, and is often not granted in other cases, especially where a long prison sentence is anticipated. In cases where a foreigner is involved, bail (if issued) may be for a higher amount than for Mexican nationals because of the increased risk of flight. Bail based on personal recognizance is not permitted. You should ask your lawyer about how bail may apply to your circumstances.

The criminal trial

In June 2008, the Mexican Constitution was amended with respect to the criminal procedure system in the country. This reform has set in motion a process to replace the Inquisitorial Criminal Procedure System with the Adversarial Criminal Procedure System, which includes Oral Proceedings (Juicio Oral). The new system is considerably more similar to Canadian criminal trial procedures.

In the new adversarial system, the parties present evidence directly and orally before the court. Opportunities to examine and cross-examine evidence and witnesses occur in an open and transparent manner. The judge must be present at all hearings and will make a decision based on the merits of the evidence presented before him/her. Oral proceedings shorten the duration of the trial.

In jurisdictions that have implemented the Adversarial Criminal Procedure System, the proceedings are now based on the presumption of innocence and trials must be public.

The Inquisitorial Criminal Procedure System does not insist upon the presumption of innocence and trials tend to take longer. The following are some of the characteristics of trials under this system:

As of October 2012, the states of Chihuahua, México, and Morelos have fully implemented the reformed proceedings. The remaining 28 states and the Federal District of Mexico City have until 2016 to complete implementation of the reforms. These include some states with major tourist destinations: Baja California, Baja California Sur, Guerrero, Jalisco, Nuevo Leٕón, Oaxaca, Quintana Roo and Sinaloa. As they transition toward the new adversarial system, some states have select regions where the Adversarial Criminal Procedure System is now in operation, while other regions of the same state may operate under the former Inquisitorial Criminal Procedure System. You should ask your lawyer which system may apply to your circumstances.

The amparo

The amparo is a procedural feature of the Mexican judicial process that resembles a motion of objection in Canada’s legal system. Its intent is to protect your rights under the Mexican Constitution if you are accused of a crime. At any point during the trial, your lawyer may propose filing an amparo if he/she considers that your rights are not being respected.

There are two types of amparo. The first is filed during the initial trial (“first instance”), which is usually related to a technicality and very seldom leads to a release. The second type of amparo is filed after the first appeal and is based on the sentence. If it succeeds, it could result in a release or a reduction of sentence, but the sentence can be confirmed if it is unsuccessful.

When an amparo is filed, a federal judge (a different federal judge if the case is already before a federal judge) has to rule on it. The trial could be delayed as a result. The most common outcome, even if the amparo is upheld, is that the trial continues. If the judge rules against the amparo, the trial will resume. Generally, an amparo takes two to six months to be heard and resolved. If the judge upholds an amparo that you have filed, there are several possible results:

Before you decide whether or not to file an amparo, it is important that you ask your lawyer to explain what it is and how it works so thatyou can understand whether it would be useful or not in your trial, the additional time involved in resolving your case, and how it would impact on your legal fees.

Duration of a trial and sentencing

Generally, a verdict is handed down 15 working days after you have been brought before the judge for a final meeting (Audiencia de sentencia or Audiencia de vista).

However, when the maximum possible sentence is less than two years, the judge has up to four months to reach a verdict. When the maximum possible sentence is more than two years, the judge has up to one year to reach a verdict. Nevertheless, there are several factors that can impact on the duration of a trial and result in a timeframe in excess of the prescribed time limits.

Amparo proceedings, translation, and changes in legal representation can all create delays, which are sometimes quite lengthy. Likewise, delays can occur when witnesses do not appear after being subpoenaed; in general, judges will give up to three opportunities for a witness to appear, but these could be months apart. Should your case pass the prescribed limit, you can ask your lawyer to clarify the procedure with the judge.

If a verdict results in a prison sentence, the time you have already spent in prison counts toward the full sentence. you, as well as the prosecutor, have the right to appeal the sentence, usually within five working days.

Transfer to a Canadian prison

Canada has a transfer of offender treaty with Mexico that enables Canadians convicted of offences in Mexico to serve their prison sentence in a Canadian penal institution if both the Canadian and Mexican governments consent to the transfer. Transfers are not automatically granted. An application for transfer can be submitted only after you have been convicted and sentenced. For further information on transfer requests, please consult the brochure A Guide for Canadians Imprisoned Abroad.

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