Predominantly, because of the pervasiveness of information technology and the affordable and competitive prices of contemporary mobile computing devices, more and more personal navigation devices (PNDs) are substantively embedded with Global Positioning System (GPS) functionality and ubiquitous networks connectivity. Therefore, the digital forensics of PNDs digital evidences becomes an urgent research issue. Meanwhile, Facebook has become a globally foremost social networking service platform. Consequently, the discovery of previous Facebook IDs on PNDs has been focused in some criminal case investigations. This paper conducts the related experiments on a Pocket PC PDA to illustrate the essence of the research. Via the design of the experiments that were carried on the Pocket PC PDA, we concluded previous user(s) information concerning the digital forensics of Facebook user account(s) that might be disclosed on the current mobile computing device. The discussions and conclusions of the paper can provide digital forensics experts as paradigms or frameworks for future related criminal case investigations regarding GPS and social networking when Facebook is involved. Copyright © 2011 John Wiley & Sons, Ltd.