(AFP) — Four Indonesians were each sentenced to 19 months in prison Wednesday after being found guilty of torturing to death two people trafficked to work on an oil palm plantation that supplied global brands.

The victims succumbed to their injuries inside two cages on the property of a local politician in Indonesia’s North Sumatra province, in the country’s latest case of modern slavery.

Rights groups say key industries in Indonesia such as palm oil and fishing are riddled with forced labour or exploitation of workers.

“The defendants have been found guilty of committing torture that caused the deaths of others, which was done together,” judge Halida Rahardini ruled Wednesday in a North Sumatra court.

One of the defendants, the son of a local politician, was also ordered to pay 265 million rupiah ($17,000) in compensation to the families of the victims.

Prosecutors had been seeking a three-year sentence for each defendant.

The oil palm plantation where the cages’ occupants were forced to work had supplied major consumer goods companies such as Nestle and Unilever, according to environmental investigative group The Gecko Project.

Unilever suspended its ties to the plantation after being confronted by the allegations while Nestle said it was investigating, the group said.

The grisly details of the case and use of modern slaves to service the facility run by company PT Dewa Rencana Perangin Angin have shone a light on human trafficking in Indonesia.

The cages, found by police conducting a graft-related raid in January, were holding 57 people, most of them drug users, male and poor, the country’s human rights commission said in a March report.

The commission said the facility had been used as an illegal drug rehab facility before its discovery to lure Indonesians who could be put to work on the plantation.

In 2015, hundreds of foreign fishermen were found held on the remote Indonesian island of Benjina where they were being forced to work in abusive conditions without pay.

© Agence France-Presse