A critical element and undeniable part of migrant smuggling investigations and prosecutions are the statements of smuggled migrants. Smuggled migrants hold unique information on smuggling ventures (see UNODC, 2010), meaning that it is often critical to secure their cooperation. However, it is understandable that migrants might be very reluctant to cooperate with State authorities. Smugglers' mere thought that migrants might be considering doing so may result in migrants and their families becoming targets for retaliation. As a result, it is important that State authorities provide the necessary protective measures and other incentives to build trust, reassure migrants and encourage cooperation.
The Supreme Court clarified that the information provided by investigative authorities to the victims/witnesses regarding the possibility of obtaining a residence permit were they to collaborate in the context of proceedings does not amount to witness tampering. Accordingly, it is not per se a valid motive to challenge the admissibility of evidence provided by such victim/witness.
SHERLOC Case Law Database on the Smuggling of Migrants - Spain
Notwithstanding measures taken by States, migrants may still refuse to cooperate for several reasons, including fear of deportation, protection of their families in countries of origin, feelings of gratitude towards smugglers and cultural or ethnic networks. Therefore, one should avoid the assumption that investigations are often based primarily on smuggled migrants' testimony. Instead, it is important to adopt and use, as appropriate, the fullest range of investigative techniques and methods of collection of evidence available (including, for example, electronic and or physical surveillance, undercover operations, searches and seizures and tracing and seizure of assets).
Similarly, defendants are in a privileged position where they can provide useful information and evidence regarding, for instance:
Defendants may contribute factually and substantially in assisting authorities to deprive organized criminal groups of their resources and proceeds of crime (article 26(1) of UNTOC).
In addition, and depending on the circumstances, cooperation by defendants may be considered as a mitigating factor in the imposition of sentences. Measures to protect defendants who cooperate may also be necessary (article 26(5) of UNTOC), given that organized criminal groups may seek reprisals against persons who provide evidence against them.
Smuggled migrants and smugglers should be interviewed as soon as possible (usually, following assistance). This is particularly important as delays make it more likely that persons will provide inaccurate information or be reluctant to do so. This may lead to the loss of important intelligence or evidence. Likewise, the longer the delay, the more opportunities there are for interferences by smugglers (for example, by offering to continue the smuggling venture, coaching migrants or making threats). Most migrants do not want to stay in reception centres after interception; unless they are identified as soon as possible, and assisted appropriately, critical witnesses may disappear and may be untraceable.