The police said it has alerted Interpol to seek the arrest of some 14 suspects wanted in connection with the attack.
"Warrants have been issued on 14 suspects having reported the matter to the magistrate's court in Tangalle", police spokesman senior superintendent Prishantha Jayakodi said.
A group of five fishermen who sailed off the coast of Devinuwara in the south on October 14 were assaulted by an unknown gang who had dumped them in the sea while fleeing with the trawler.
Two people were rescued but three others are still missing and presumed dead.
Police later said that the hijacking of the trawler was carried out by a group who are involved with human trafficking to Australia on board fishing trawlers.
Sri Lanka Navy had rescued at least two of the fishermen who had been critically injured when found by a merchant vessel.
Since early this year multiple Sri Lankan fishing vessels had carried an influx of asylum seekers to Australia.