Terrorists relying on newer technologies like proxy internet servers and Voice over Internet Protocol (VOIP) as indicated by Pakistan's probe into the recent Mumbai attacks pose a new challenge to police investigations, feel cyber experts.

"There is so much data communication on the internet at all times that it is very difficult to detect VOIP that is malicious in nature. Even if it is detected, decoding the communication, tracing the locations of the terrorists, monitoring them, etc, is very difficult," says Ankit Fadia, a cyber security expert.