A 45-year-old Bangladeshi, believed to be one of the 'boat people' refugees, died in June while under detention at Kedah’s Belantik Immigration Detention Centre, migrant rights NGO Caram Asia has revealed.

The mysterious death has sparked queries on the health conditions of other detainees still held at the camp in the Sik district which housed a flood of Rohingya and Bangladeshi refugees who arrived in May.

Caram Asia regional coordinator Muhammad Harun Rashid said the NGO had sent the remains of the deceased - identified as Abdul Roshid Attab Uddin - back to Bangladesh.

"I have also visited his family and they are in dire need of funds. We managed to collect US$1,500 for his family to aid them now that they have lost Abdul Roshid," Harun told Malaysiakini when contacted.

Harun said no one knows the cause of Abdul Roshid’s death as a medical report has yet to be issued.

He expressed concern about the health conditions of two other refugees at the detention centre, which the NGO is currently probing.

"Abdul Roshid's family wants to know how he died but until today, we have yet to be provided with a medical report," he added.

Documents, including a death certificate made available to Malaysiakini, show that Abdul Roshid, who hailed from Narsungdi’s Velanagor district, died on June 5 at 3.20pm. He left his country in April.

He was pronounced dead at Alor Setar's Sultanah Bahiyah Hospital, with the death certificate's entry for cause of death stating "pending laboratory analysis".

On July 22, Kedah Immigration Department deputy director Phon Ai Liap issued a letter saying he had no objection to Abdul Roshid’s remains being sent back to Bangladesh.

When contacted, Belantik Immigration Detention Centre director Amir Mansor declined to comment about the case.

High Commission declines comment

On July 29 the remains were sent back to Dhaka and received by Roshid's brother, Abdul Kashem, at the Hazrat Shahjalal International Airport.

When contacted, Bangladesh High Commission first secretary Musharrat Jebin Musharrat confirmed the death but refused to disclose further information.

"Why do you need it? Sorry, I cannot hand over any medical report or documents to you," she said when contacted, before ending the call abruptly.

Harun said the Bangladeshi was one of many 'boat people' who were placed at the Belantik camp in May after hundreds of them were abandoned at sea.

"There are about 200 still remaining there awaiting their fate," he said.

On May 11, it was reported that 1,058 Rohingya and Bangladeshi migrants were arrested after landing at a beach in Langkawi, Kedah ( photo ).

They were stranded at sea due to Thailand’s large-scale move to combat human trafficking syndicates.

Thailand had undertaken this following the discovery of more than 30 bodies in mass graves in the southern part of the country in early May.

The dead are believed to be among the more than 100,000 stateless Rohingya Muslims who have fled violence and poverty in Myanmar since 2012.