According to the Singapore police, the men had seized millions of dollars, as well as a small tanker at the Pulau Bukom industrial site, which is located south of Singapore’s main island.

Oil refining industry has played an important role in improving Singapore's wealth the recent years, however, the specific region faces a lot of illegal oil trading issues, Reuters reported.

The police investigation was initiated after Shell contacted the authorities, during last summer, after which the police began simultaneous raids across the country, which resulted in some arrests.

Namely, nine Singapore nationals were charged for theft, with eight of them working for Royal Dutch Shell's subsidiary in Singapore. Moreover, another two Vietnamese were charged, after receiving stolen products.

The company confirmed this week that out of the eleven men that were charged, eight of them were currently working or used to be working for Shell Eastern Petroleum, Reuters concluded.