Intrusion detection is a very sensitive and major concern in wireless sensor networks. In border areas, sensors are installed to discover the presence of enemies or any trace passing in a prohibited area or any vicious moving object in the region of interest. In order to gain access to a region of interest, an intruder can take various paths, i.e., it can move along a straight line, follow a zigzag path or a curved path and move at a particular angle to cross the region without being detected and to improve its attacking ability. This paper formulates and analyzes $$\kappa$$ -barrier coverage probability which acts as the intrusion detection probability for an intruder when the intruder follows different paths at different path angles with respect to the shortest path to cross the region of interest in a mobile sensor network. Furthermore, the effect of different network variables such as node density, sensing range, intrusion path angle and the ratio of sensor to intruder velocity on intrusion detection probability are also investigated. It is believed that the proposed model renders an effective tool to incorporate the intruder’s movement pattern in the design of an advanced finite wireless sensor network.