This seizure questions the oft-held impression that Bangladesh only faces a narcotics threat from neighbouring Myanmar, from where heroin and methamphethamines are smuggled in.
That's because the cocaine seized at Chittagong is said to be produced in Uruguay.
Chittagong Detective Branch Deputy Commissioner Kusum Dewan told bdnews24.com on Saturday about the formation of the interrogation panel, which he leads.
The other members of the panel are additional commissioners, assistant commissioners and inspectors.
Police have already remanded Prime Hatchery Manager Golam Mostafa Sohel.
Prime Hatchery is associated with Khan Jahan Ali Limited that imported the edible oil.
Its owner Noor Mohammad is absconding.
The three other arrested are garments exporter Atikur Rahman, shipping lines firm official AK Azad and Mostafa Kamal whose relative Bakul Mia, staying in the UK, is suspected to be the linchpin of the cocaine smuggling syndicate.
The customs has formed an investigation panel of four after cocaine was traced in the oil on June 28.
They suspect that smugglers from UK, Bolivia, and India were in the ring, along with those of Bangladesh.
They said the cocaine from Uruguay was bound for India.
The container with the barrels of the edible oil landed at the port on May 12.
Tests found that one-third of the 185-kilogram sunflower oil of a barrel is liquid cocaine.