The North Sumatra Police have foiled two separate attempts by two trafficking groups to smuggle dozens of workers from the province to neighboring Malaysia.

The latest case was uncovered by the police on May 3 in Sei Pasir village in Asahan regency.

The other case was uncovered on April 7 in Bagan Asahan village located in the same regency.

North Sumatra Police chief Insp. Gen. Rycko Amelza Dahniel said the police’s crime investigation unit had arrested a total of 16 people believed to be smugglers in the two plots. They allegedly attempted to smuggle 67 illegal workers to Malaysia.

Rycko said the perpetrators had tricked the victims, mostly from Java, West Nusa Tenggara (NTB) and Sumatra, into believing they would be employed in lucrative jobs in Malaysia, asking them to pay money before being transferred to their employers there.

“They had to pay from Rp 1 million [US$75] to Rp 3 million in order to work in Malaysia,” Rycko told The Jakarta Post on Friday.

(Read also: Police raid E. Jakarta clinic allegedly involved in human trafficking)

The police have learned that the alleged perpetrators, consisting of local brokers and recruiters, were part of a human trafficking syndicate that had been operating for a long time in “most of Sumatra and Java.”

The alleged smugglers could face a maximum 15 years of imprisonment and Rp 600 million in fines if convicted under the 2007 Human Trafficking Law.

The head of the North Sumatra Police’s General Crime Investigation Division, Sr. Comr. Nurfalah, claimed the ongoing investigation into the two cases had discovered that the two smuggler groups had operated for 10 years before their felonies were revealed.

Rycko said the alleged smugglers had hopped from region to region in the province to find people to be smuggled overseas, using a ship based in waters off Tanjung Balai in the province to take them to Malaysia.

“Somebody will pick them up when arriving in Malaysia. [That person] will then bring them to entertainment centers [like nightclubs], which were not the places promised earlier by the perpetrators,” Rycko said.

Some 19 victims have been transferred to the province’s Social Affairs Agency for social treatment. Forty-two of the victims have been returned to their respective families and six victims, believed to be residents of West Java, Banten and Aceh, are still in police custody for further questioning.

“We will transfer them to their regions in the near future,” Nurfalah said.

The numbers of human trafficking cases are skyrocketing in Indonesia, with cases increasing from 188 in 2013 to 326 in 2014 and 548 in 2015, according to a Foreign Ministry estimate.

In the middle of last year, six top government agencies — the Foreign Ministry, the Law and Human Rights Ministry, the Women’s Empowerment and Child Protection Ministry, the Social Affairs Ministry, the National Police, the Attorney General’s Office and the Agency for the Placement and Protection of Indonesian Migrant Workers — formed a coalition to combat human trafficking in response to the rising trend of the crime.

The six bodies signed a memorandum of understanding that covers six areas of cooperation: data and information exchange, victim identification, trafficking prevention, law enforcement and capacity building and repatriation and rehabilitation of victims.