Identification and Tracking of online digital identity has been significant issue around efforts on cyber security. The purpose of this research is to demonstrate how to utilized information being emitted from digital devices carried by suspicious user. In this paper, techniques to identify owner of digital devices connected to the Internet or local network are proposed. Techniques include tracing physical id of network interface, profiling of network traffic pattern of devices, Bluetooth device signals, web browser finger printings, and header information of e-mail messages. Each devices connected to computer network has its own finger print such as physical MAC address, network traffic generated by operating systems and its installed applications thus such information can be applied to identify and track unique digital device. If the device is personal item such as smartphone or personal computer owned by a specific person this information is being able to use to detect and trace location of the person. Each web browser installed on such devices also has its unique characteristics such as version, installed fonts, and difference in its settings, such information can be used to identify a person. E-mail message has significant information in its header, by analyzing messages headers certain amount of information of its sender are extracted. This is also used to detect impersonation of a message sender. By integrating these information obtained through such monitoring activity and related network sensors we are able to identify existence and physical location of a targeted personnel, to monitor their behavior and also we are able to use such data as evidence for law suites. Preservation of privacy is the issued to be considered for such application and this would discuss how to balance between user privacy and traceability of users in certain types of network.