Singapore police have arrested 20 people after oil worth £6.4m was siphoned from a Shell refinery.
Authorities have so far charged 14 of those arrested after uncovering a complex, cross-border plot to steal the oil.
They have seized at least one oil tanker and millions of dollars in cash.
Court documents listed 18 dates between 24 July 2017 and 7 January 2018 when tens of thousands of tonnes of oil were stolen.
Most of the thefts from Shell’s Pulau Bukom site, which is just 3.4 miles from Singapore’s main island, took place during the refinery’s normal working hours.
Eleven Singaporeans and three Vietnamese men were the latest to be charged on Thursday, with several granted bail.
Eight of the Singaporeans were Shell employees while two others worked for Sentek Marine and Trading, one of Singapore’s biggest marine fuel suppliers.
The investigation found one of three vessels used to transport the stolen oil was a Sentek ship named Sentek 26.
Another Singaporean charged worked for British-listed Intertek, which specialises in quality and quantity assurance, including for fuel products.
The three Vietnamese men were charged with receiving stolen property aboard two other ships, Prime South and MT Gaea, both registered in Panama.
Over the last three months the three vessels used have travelled between ports in Singapore, Vietnam, Thailand and Indonesia, shipping data from Thomson Reuters Eikon shows.
Some of those charged are due in court on 29 January.