Indonesian police are investigating the death of a local official in the Ministry of Fisheries and Maritime Affairs to see if it is linked to a slavery probe in the remote, eastern island village of Benjina, a government official said Wednesday.

Yoseph Sairlela's body was found Saturday at a hotel in a leafy neighborhood of the capital, said Asep Burhanudin, director general of sea and fishery resources.

Although there was a wound on the side of the victim's face and a bruise on his forehead, an initial examination determined that they were not the cause of death and Sairlela died of a heart attack, Asep said. He said the results of an autopsy are still pending and the police investigation is continuing.

Minister Susi Pudjiastuti, meanwhile, has launched an internal investigation into the case, he said, noting that Sairlela was supposed to be a key witness in a case surrounding the use of forced labor by Thai-run fishing trawlers in Indonesia's Maluku islands.

The circumstances behind the 51-year-old's death remained unclear Wednesday.

Asep told a news conference that the victim met with an unknown person in Surabaya, the capital of East Java, last Thursday and traveled to Jakarta the following day to buy spare parts for the ministry's speedboat on the island of Dobo — about 90 minutes from the island village of Benjina by sea.

Sairlela met his daughter hours before his death, Asep said, and she reported that her father "seemed to be unhealthy, and went back to the hotel." She did not mention any wounds.

She learned soon after that he was "in critical condition" and had been rushed to a hospital, Asep said.

Padjiastuti called for a further investigation because of the victim's links to allegations — first published by The Associated Press — that hundreds of men from Burma, Cambodia, Laos and poor parts of Thailand were being forced to work on fishing trawlers around Benjina for little or no money.

Some men were locked in a cage. Many complained of working 20- to 22-hour days, saying they were beaten if they were caught taking a rest or slacking off due to illness.

Most of the workers said they were brought to eastern Indonesia from Thailand, some after being tricked or sold.

The AP investigation found that the fish they caught entered the global seafood supply chain.

After visiting Benjina earlier this month, Padjiastuti's ministry evacuated more than 300 of the men to another island in the Malukus, Tual, saying they were not safe.