At least 67 Rohingya refugees have escaped from a temporary camp in Lhokseumawe City, Aceh, Indonesia and are believed to have been trafficked to neighboring Malaysia, local officials said.

Lhokseumawe Police chief Adj. Sr. Comr. Eko Hartanto said the Rohingya made their escape from the refugee camp in Meunasah Mee Kandang village in the coastal district of Muara Batu throughout the past year. Police believed human trafficking syndicates were involved.

Eko said the syndicate members were from several areas in North Sumatra province, which is south of Aceh, including Medan, Deli Serdang, Tebing Tinggi and Tanjung Balai. He added that they would pick up Rohingya refugees in Aceh and bring them down to Medan before trafficking them to Malaysia through the province’s Tanjung Balai Port.

“This is the work of syndicates. This is their known modus [operandi],” Eko told the Jakarta Post on Friday.

The police have been tracking the syndicate’s operations for some time, he said. Syndicate members would damage the engine of incoming Rohingya boats, knowing that they would be towed and placed in temporary refugee camps in Aceh, before helping them escape.

“We already have 12 similar cases with 14 suspects. We aim to put a stop to this,” Eko said.

A Myanmar military crackdown in 2017, which United Nations investigators said amounted to genocide, forced 750,000 Rohingya to flee across the border into Bangladesh’s southeast coastal district of Cox’s Bazar, where many ended up in sprawling refugee camps.

Thousands have since paid smugglers to get them out of Bangladesh, enduring harrowing, months-long sea journeys punctuated by illness, beatings by traffickers and near-starvation rations to reach Indonesia and Malaysia.

Many of these boats would enter Indonesian waters in Aceh before being saved and brought ashore by local fishermen or authorities.

Marzuki, the spokesman of Lhokseumawe’s Rohingya Refugee Management Task Force, said the refugee camp in the city had loose security, making it easy for the refugees to escape. He said they would often break the camp’s fence to escape.

According to Marzuki, the most recent escape happened on Thursday morning when 31 Rohingya made their way out by cutting a part of the camp’s corrugated zinc fence.

“None of those escapees have returned. We now have 41 Rohingya refugees in the camp after 67 got out,” Marzuki said.

Many of the escapees are part of 105 Rohingya refugees who arrived in Aceh late last year.

Officials said all Rohingya refugees in Aceh were under the responsibility of the UN’s refugee agency. Local military and police only have the authority over the refugees in the first 10 days of their arrival in Aceh. After that, they are turned over to the UNHCR.

Eko said it was the responsibility of the UNHCR to remove refugees from the temporary camp to a permanent one.

“The removal has not been done so far,” the police chief said.

UNHCR spokeswoman Mitra Suryono confirmed the escapes.

“They left the camp, even though there was security,” Mitra told the Jakarta Post.

According to her, the agency has advocated the refugees on the risk of irregular travel, including the danger of using trafficking networks. The agency understood that the refugees had left the camp with help from “outside parties”.

Mitra said the UNHCR continued to communicate and coordinate with the local authorities, including giving them all the information they had.