The growing interest in location based service and wireless security in WLAN necessitates the development of an effective scheme which can locate an attacker in a WLAN to make him account for his misdemeanors and expel him out of the network. On the other hand, while localization has been an active area of research recently, current research of secure localization mostly focuses on getting correct locations of legitimate users despite the existence of malicious attacks. There is little effort on how to locate an attacker who is equipped with advanced radio technologies to distort traditional localization system's location estimation. To fill in this challenging technical void, in this paper, a novel localization scheme is proposed, called ALD, which can locate the attacker with traditional range-free localization equipments. The main idea here is to use coordination of multiple APs to locate the attacker and optimize the process with a finite horizon discrete Markov decision process (MDP). An approximation algorithm is proposed to pre-compute the MDP efficiently. The solution then can be stored in APs without requiring any strong computation capability and special hardware. The ALD scheme can be supported by IEEE 802.11 and many other wireless network standards.