First, the newest sign is examined in context: exact room, surface, date, number and direction. A specimen is retained safely where possible. Previous sprays, traps, cleaning or repairs are disclosed because they may alter distribution.
Next, likely harbourage is checked close to that point. The search widens only along credible connections such as service penetrations, adjoining furniture, stored materials or shared voids. Areas that cannot be opened are recorded rather than treated as clear.
The working explanation must account for both supporting and missing evidence. Where confidence remains low, monitors can test location and species. Where identity and extent are adequate, the technician chooses a method for the lifecycle, surfaces and risks to children, pets or other non-targets.
In rented or managed property, a landlord or agent may need to authorise cellars, risers, roof spaces or building repair. A limitation in access remains part of the diagnosis.