Mutual Legal Assistance

Practitioners should generally not begin their international cooperation efforts with the submission of an MLA request. If available, informal assistance channels should be explored first so that practitioners connect with their counterparts to discuss what will be needed to execute the request and to address potential barriers. Once a practitioner determines that an MLA is required for certain needed action—such as the production of financial records, obtaining compulsory testimony or a search and seizure, or enforcing a provisional restraint order—numerous requirements and procedures will need to be adhered to, some of which are described below. 

Requirements will vary from jurisdiction to jurisdiction, so practitioners should confirm their applicability beforehand with the foreign central authority. Consulting with foreign counterparts or other contacts can be helpful in this regard, although many jurisdictions will require the practitioner to proceed on a formal basis through their own central authority when a formal request is being prepared or has been sent. In addition, many jurisdictions publish information on their central authority’s website that may state the requirements, and some even provide sample forms for preparing an MLA request that is acceptable. The United Nations Office on Drugs and Crime operates a directory of central authorities and has developed an MLA request writer tool to assist practitioners. Finally, publications by nongovernmental or multilateral organizations may also provide assistance. 

Legal basis for International Cooperation

To proceed with an MLA request, there must be a legal basis for cooperation; and this must be specified in the request. This legal basis may be provided in (1) multilateral conventions, treaties, or agreements containing provisions on MLA in criminal matters; (2) bilateral MLA treaties and agreements; (3) domestic legislation allowing for international cooperation in criminal cases; or (4) a promise of reciprocity through diplomatic channels (referred to as “letters rogatory” or “comity” in some jurisdictions). It needs to be noted that the absence of a mutual legal assistance agreement or relevant law may significantly complicate proceedings and impede the successful outcome of a case.  


Selecting a legal basis to include in the formal MLA request 

In selecting the legal basis to include in an MLA request, many practitioners have found it most helpful to list all relevant treaties, agreements, or legislation that apply, in order of preference. This practice increases the opportunity for applicability: because the types of assistance and potential reasons for refusal vary from treaty to treaty, the request may be acceptable under one legal basis and not under another. The list should be in order of preference. A bilateral treaty is generally a good option if the treaty properly implements the main principles of important multilateral treaties such as the UNCAC. Bilateral treaties are tailored to the legal traditions and options of the two contracting jurisdictions (in contrast to the “one size fits all” approach of the multilateral treaties. The relevant treaties followed by any domestic legislation, usually allow for faster cooperation than do a promise of reciprocity and letters rogatory.


General Requirements 

Generally, the request must be related to a criminal matter, although some jurisdictions will provide assistance on NCB confiscation requests (because they generally arise in connection with a criminal investigation) and in civil and administrative cases. Although most jurisdictions will permit requests during the investigation stages, others will have more onerous requirements for the provisional seizure or restraint of assets (such as requiring that charges have been instigated or final confiscation has been ordered). Many jurisdictions will not provide assistance if the criminal proceedings have concluded. 

Many jurisdictions will require some showing of dual criminality, meaning that the conduct underlying the request for assistance is criminalized in both jurisdictions. Different jurisdictions address this requirement in different ways however more frequently jurisdictions apply a conduct-based approach (that is, they look at the underlying conduct behind the terminology and require that the conduct is a criminal offense under the laws of both jurisdictions). In any event, the use of informal assistance is paramount to discuss, identify, and overcome (if possible) any potential barriers that the dual criminality requirement may pose. The conduct-based approach can be helpful in corruption cases because some of the more specific offenses involved are not criminalized in all jurisdictions for example, illicit enrichment, bribery of foreign public officials, tax avoidance, or extended confiscation. It will be important to describe rather than merely list the offenses, because the requested jurisdiction may not have the relevant expertise of the legal system of the requesting country and may have to assess whether the conduct is punishable under a different name under its domestic laws.  


Overcoming Dual Criminality—Illicit Enrichment and Corruption of Foreign Public Officials 

The offenses of illicit enrichment (a significant increase in the assets of a public official that the official cannot reasonably explain as being derived from lawful earnings) and bribery of foreign public officials have not been criminalized in a number of jurisdictions. If strictly interpreted on the bases of terms, there would be no dual criminality—and thus no assistance available—from those jurisdictions. 

This barrier may be overcome when dual criminality is assessed on the basis of conduct because the facts under investigation in the requesting jurisdiction may constitute another offense in the requested jurisdiction. For illicit enrichment, the conduct that constitutes the illicit enrichment may be categorized as another offense under the law of the requested jurisdiction (for example, accepting a bribe). With bribery of foreign public officials, the requested jurisdiction may consider the offense to be bribery of a national official, not a foreign official. This approach was confirmed in a 2003 ruling of the Swiss Federal Supreme Court (ATF 129 II 462). The Court held that dual criminality was met on corruption charges, despite not having corruption of foreign public officials in Swiss law. In reaching this verdict, the Court looked at the facts and conduct, and held that the requesting jurisdiction was able to fulfill the requirement on the basis of another offense: passive corruption of national public officials was an offense under the Swiss system. Once the parallel offenses—based on the same conduct—are determined, the dual criminality requirement is met. 

Practitioners using this approach must take care when stating the facts and offenses in their MLA requests. For example, it may not be sufficient to submit a request that states:  

Mr. X is a public official who earns US$3,000.00 per month at the Ministry of Transportation. When he began his position five years ago, he had no savings; now he has US$5 million. He was unable to explain this increase and is found guilty. 

Instead, it will be important to include additional facts that may support an offense in the foreign jurisdiction: 

Mr. X is responsible for procurement of construction contracts and in the past three years he has awarded three major contracts to new companies. His bank account statement shows he received two deposits of US$400,000.00 just prior to the awards. Recently US$1 million was wired to a bank account in your jurisdiction Y. 

Asking counterparts in the requested jurisdiction to review a draft of the MLA request prior to submission may facilitate this procedure. The counterpart may be able to offer drafting suggestions that make the request more easily enforceable.


Many jurisdictions require a reciprocity assurance, a written statement that the requesting jurisdiction will provide the requested jurisdiction with the same type of cooperation in a similar case in the future. And many jurisdictions require the requesting jurisdiction to specify if it wishes the request to be treated as confidential. In addition, jurisdictions may require an assurance that the requesting jurisdiction will use the information supplied only for the case described in the request for assistance—not as evidence in another case or disclosed to a third party. Finally, some jurisdictions may require a commitment to pay any costs and damages incurred by the requested party during the course of executing the request. These assurances may be waived on a case-by-case basis, but waivers must be discussed with the other jurisdiction. Some practitioners hesitate or refuse to provide these assurances because they are not used in their own jurisdiction, and the practitioner is unsure whether he or she has the authority to provide them. However, these assurances are often not optional, and assistance may be refused if they are not provided or addressed prior to the submission of the request.  

Evidentiary Requirements

Practitioners usually have to provide sufficient admissible evidence to officials to enable them to meet the evidentiary threshold mandated by their courts in executing a request. This can be challenging because admissibility requirements vary among jurisdictions. Once it is determined that a formal MLA request is required, the following three step process should be considered prior to submission of the request: 

STEP 1. Determine what is needed (for example, production or seizure of financial or business records, search of a location, seizure or restraint of assets, or confiscation). It is often best to use a step-by-step approach to requesting MLA, rather than to request everything at once. 

STEP 2. Determine the least intrusive means for obtaining the needed information, as well as the standard of proof and evidence required by the requested jurisdiction (for example, specific facts, location of the assets, link between asset and offense, and final court order). 

STEP 3. Determine the format for admissible evidence in the requested jurisdiction and any other documents required (see Section 9.2.4 below for additional details on form and content). 

MLA requests must be in writing and must meet the language, content, and format requirements of the requested jurisdiction, applicable treaty, or practitioner’s domestic central authority to reduce the chances of refusal to implement an MLA request. Some treaties (including United Nations Conventions) elaborate prohibited grounds for refusal, such as the involvement of fiscal offenses or bank secrecy. 


Bank Secrecy and Fiscal Offenses—Prohibited Grounds for Refusing MLA Requests  

Bank secrecy and fiscal offenses are generally prohibited by the United Nations Conventions as reasons for refusing to provide assistance. Where applicable, practitioners should refer to treaty provisions: 

  1. Fiscal offenses: UNCAC article 46(22), UNTOC, 18(22), and United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances article 3(10) prohibit MLA refusals on the sole ground that the offense involves fiscal matters. 

  2. Bank secrecy: 

  • OECD Bribery Convention article 9(3), UNCAC article 46(8), and UNTOC article 18(8) expressly prohibit MLA refusals on the ground of bank secrecy. 
  • UNCAC article 31(7) and UNTOC article 12(6) require states parties to empower courts or other competent authorities to order seizure of bank, financial or commercial records in domestic cases and in international cooperation. 

  • UNCAC article 40 requires states parties to ensure there are appropriate mechanisms to overcome obstacles that arise from bank secrecy in domestic criminal investigations. Although this provision applies to domestic investigations, it still demonstrates efforts toward reducing bank secrecy, and would help in cases where the requested jurisdiction is asked or opts to pursue a domestic case for money laundering on the basis of the foreign predicate offense. 


Practitioners should address these potential obstacles proactively and before the request is sent (if possible), because it becomes much more difficult to overcome a refusal when it has been issued. Upon submission, practitioners will have to follow up on its progress. If possible, practitioners should speak directly with the person assigned to execute the request because this opens the opportunity to clarify any terminology or translation issues, check if requirements are met, and offer additional information. The requesting jurisdiction may be asked for more information to support the request. If no response is received or an MLA request is refused, practitioners should contact counterparts in the requested jurisdiction to determine the reasons for the lack of a response or for a refusal. United Nations conventions require states parties to provide the reason(s) for any refusal. If there is still no response or a refusal to address possible errors in the reasons for refusal, look for other avenues. Applying third party pressure through other jurisdictions or international organizations has been helpful in some cases, particularly in multijurisdictional cases.