Piracy, infiltration, firing at crowds, using explosives, hostage-taking, suicide missions: the militants who attacked Mumbai had learnt every trick in the extremist's handbook, experts say. "It is like during guerrilla warfare," Gerard Chaliand, an independent specialist on asymmetric conflict, said. "Groups learnt from experience and the mistakes of those who had gone before them. "There is a sort of accumulation of knowledge every time," he added, declaring that he was "unsurprised" by the methods employed during the 60-hour attack on India's financial capital between November 26 and 29. "They used every available bit of information and applied it in a rapid manner," he said. "Piracy is not a classic tactic but it has already been used in the southern Philippines" by Islamist insurgents, he noted.