Speaking after an hour-long meeting with his team to discuss the case's progress at Songkhla's Marine Police Office on Monday, assistant police chief Pol Lt Gen Chakthip Chaijinda said he assigned Pol Maj Gen Pisit Pisutisak, chief of Provincial Police Region 9 to undertake the probe and instructed him to complete it within three days before tracking down suspects.
Pol Lt Gen Chakthip said the probes are moving swiftly as Indonesia gave Thai authorities useful information.
''We have now been able to identify all the Thai crew [allegedly involved in the murder of the Indonesians]. But we can't disclose their names at the moment as investigations are ongoing,'' he said.
He said 12 Thai crew members were linked to the case, with two of them treated as witnesses.
The Royal Thai Police began their investigations on March 15 after being asked for help by the Indonesian embassy in Bangkok.
A task force from the Songkhla police, the Crime Suppression Division, Immigration Bureau and Marine Police Division was set up.
A source in the investigation team said the two witnesses admitted the crew of the Sor Nattaya 7 had hit the heads of the two Indonesian navy personnel with a hammer and stabbed them to death before dumping their bodies in Indonesian waters.
The source said the witnesses did not explain why the crew killed the Indonesians.
The incident took place about 9pm on March 8 when Sgt Maj Alfriansyah and a navy employee named Edit boarded the Thai fishing vessel Sor Nattaya 7 while sailing in Indonesian waters in the Natuna Sea, the witnesses told the source.
The men boarded the trawler to locate Thai fishermen from another boat who had fled after they were involved in a confrontation with other Indonesian naval officers on shore. They took control of the vessel and continued to Talampa Island in Indonesian waters before being killed.
Shortly after allegedly killing the two Indonesians, the trawler's captain sped towards Thai waters to flee Indonesian authorities before mooring at a pier behind Koh Nu island in Songkhla on March 13.
Investigators have yet to locate the Sor Nattaya 7's captain, identified as Pad, who reportedly boarded another Thai trawler heading for Pattani while his boat was returning to Songkhla pier.
The source said investigators searched the boat — repainted to hide it from Thai police — and seized a gun believed to belong to one of the Indonesian navy officers.
The source said the captain and crew of the Sor Nattaya 7 were probably involved in the double murder and the fishing vessel was seized and taken to Songkhla's Marine Police Office as evidence to substantiate charges against the captain and his crew.
The incident spurred Indonesia to ban Thai trawlers from operating in Indonesian waters. Such a ban could cost Thailand about 30 million baht a day in lost revenue.
Pol Lt Gen Chakthip said he asked the Indonesian consul in Songkhla to contact the Indonesian embassy in Thailand so it could lift the ban as soon as possible.
Watcharin Panurat, deputy spokesman of the Office of the Attorney-General (OAG), said because the case took place outside Thailand, Indonesia must ask the OAG to form a panel to arrest the suspects.
Mr Watcharin said the OAG will appoint Mr Surasak Srirattanatrakul, director-general of the Office of the Investigation, to join the panel.