A wireless sensor network consists of spatially dispersed self-directed sensors to monitor the environment conditions. This paper supports in network top-k query process over uncertain data in a distributed wireless sensor network. The authors develop the notion of necessary Set for efficient in-network pruning of uncertain data in a distributed setting. Based on the necessary sets, they propose, necessary set-based, algorithm for in-network processing of queries in a two-tier hierarchical sensor network. For providing privacy proposing locked Q protocol that that prevents attackers from gaining information from both sensor collected data and sink issued queries.