NAGAPATTINAM: Six fishermen from Nagapattinam and Mayiladuthurai districts were allegedly assaulted and robbed at sea by assailants said to be from Sri Lanka on Friday night. Sources said fishermen C Kumar, K Jegan and N Lakshmanan -- all from Mayiladuthurai camping in Nagapattinam's Kodiyakarai for the past two months -- on Friday afternoon ventured into sea in a motorised boat. …