The continuing rise of network security threats and network attacks have motivated accelerated studies on network forensics. Typically, data collected in a networked system is often used to investigate security threats. One of the principles and techniques of network security is packet analysis, which is a branch of network security that studies insecure protocols. In order to help with the forensic investigation and facilitate the fight against security and privacy threats, we carried out an active inspection of network packets on a BitTorrent client. This paper proposes a capture and analysis technique for network packets using Wireshark. Network traffic of P2P networks was monitored, captured, and analyzed. The analysis results showed that the proposed technique successfully identified the source and location of threats on the network, which can be verifiable as credible digital evidence for forensic investigations