Neighborhood discovery is a critical part of wireless sensor networks, yet little work has been done on formal verification of the protocols in presence of both intruder nodes and mobility. We present a formal trace-based model to verify protocols doing neighborhood discovery, and we provide a formal definition of (1)neighborhood and (k)-neighborhood. We also analyze a protocol from the literature, and show some conditions needed for its correctness. Finally, we present the groundwork for a protocol which discovers (k)-neighborhood based on (1)-neighborhood data under some assumptions, and prove that it remains secure even if an intruder interferes.