Wireless sensor networks (WSN) collect and report event information to users in many applications (e.g. monitoring, tracking). Due to the lack of infrastructure and management in the sensor field, WSN are vulnerable to many security attacks. In false report injections attacks, attackers inject false reports into the network through compromised nodes. The false reports cause false alarms at the base station (BS) and waste energy at forwarding nodes. In the statistical en-route filtering scheme (SEF), a countermeasure to the attacks, sensor nodes detect and drop false reports by endorsing and verifying event reports using shared keys. In SEF, each node verifies received reports based on fixed probability and do not consider sending nodes. For this reason, unnecessary energy consumption occurs. In this paper, we propose the verification probability control method in sensor networks. In the method, each node controls its verification probabilities for its neighbor nodes. The number of recent valid reports, hop counts from the BS and the last verification probability are used to determine the verification probability for a node. We confirm that our method decreases energy consumption of filtering schemes in sensor networks.