Privacy Enhancing Technology (PET) is the technology responsible to hide the identification of Internet users, whereas network forensics is a technology responsible to reveal the identification of Internet users who perform illegal actions through the Internet. The paper identifies the collision of these opposite-goal technologies and describes what happens in case they come across. Can a Network Forensics protocol discover the identification of an Internet user who is trying to be anonymous behind a PET? The paper also proposes a way to bridge and eliminate the gap between these two technologies.