Undermining, nuisance and risk in your properties
Cannabis farms, drug labs, money laundering through property, persistent nuisance: criminals and nuisance-makers use homes and commercial premises differently than agreed. We establish the facts and deliver the file you need to act.
Real Estate
Undermining, Nuisance and Property Risk Assessment
Criminal undermining occurs where the underworld uses the legitimate economy: cannabis farms in rental homes, synthetic drug labs in commercial premises, storage of weapons or stolen goods, and money laundering through property transactions. For landlords, housing associations, property managers and owners' associations this means legal risk, reputational damage and direct danger to residents, from fire risk at cannabis farms to explosion risk at labs. Nuisance is the smaller brother with the same effect on a building: according to the 2025 Safety Monitor of Statistics Netherlands, 46 percent of Dutch residents experience one or more forms of social nuisance in their own neighbourhood (CBS, Veiligheidsmonitor 2025, in Dutch). In both cases: without documented facts you cannot give notice, cannot terminate and cannot call on the municipality. On this page we combine three investigations: undermining investigation, nuisance investigation and a preventive risk assessment of your portfolio.
What we investigate
Undermining investigation
Signal analysis: abnormal energy consumption, covered or blacked-out windows, short visits at unusual hours, cash rent payments, tenants who do not respond. Tenant profile: ties to criminal networks via open sources and registers. Property investigation: establishing actual use from public space and, with the consent of the person entitled, on site. Transaction analysis: characteristics of money laundering in purchases and sales. Where you wish, we coordinate with the municipality, police or the regional RIEC partnership.
Nuisance investigation
Noise, intimidation, pollution, drug use in communal areas: residents expect you to act, but without a file your position is weak. We document the nuisance objectively with date, time and duration, record statements from neighbours and establish who is causing it. The file can be used for a warning, termination proceedings or a request to the municipality.
Property risk assessment (preventive)
Not every risk in a portfolio is visible. We screen tenants and users for signs of housing fraud, subletting, undermining and payment risk, check whether the actual use of properties matches the lease and the zoning, and assess your internal processes (screening at intake, follow-up of reports). You receive a risk picture per property or building with concrete recommendations. Suitable as a periodic assessment for housing associations, investors and managers.
Legal framework: what you can do with the file
A lease of built property can in principle only be terminated by the court; if a property has been closed by the mayor under Article 13b of the Dutch Opium Act, the landlord may terminate out of court (Article 7:231(2) Dutch Civil Code). The tenant must behave as a good tenant (Article 7:213 DCC) and may not simply let others use residential premises (Article 7:244 DCC). In cases of serious and repeated residential nuisance the mayor can impose a behavioural order under the Residential Nuisance Act (Article 151d Municipalities Act); between neighbouring plots the prohibition of nuisance in Article 5:37 DCC applies. Withdrawing housing from residential use or splitting it without a permit is prohibited (Article 21 Housing Act 2014). A landlord must act in accordance with the Good Landlordship Act; a careful, lawful investigation fits within that. All links are to the Dutch statutory texts.
How does the investigation work?
you share the signals or the portfolio; we assess severity, urgency and the permissible approach.
methods (open sources, surveillance, resident statements, file analysis), timeline and fixed price.
screened investigators work discreetly, within the Wpbr, the GDPR and the privacy code of conduct; in case of acute danger we advise contacting the police or municipality immediately.
a file with findings, risk assessment, evidence and recommendations, aligned with your lawyer or the municipality.
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⚖️ Legal framework
SAJ Recherche operates in compliance with the Dutch Private Security and Investigation Agencies Act (Wpbr) and the General Data Protection Regulation (GDPR/AVG). All investigations are conducted under POB licence 8779, issued by the Ministry of Justice and Security.
Legal recognition and licences
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Frequently asked questions
How do I recognise undermining in my property?
What should I do if I suspect undermining?
Can a nuisance file lead to termination of the lease?
Can neighbours cooperate anonymously?
Does SAJ Recherche work with the police and the municipality?
Can I be held liable as a landlord?
What does an investigation or risk assessment cost?
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