As Thai and Malaysian authorities continue their hunt for hidden graves of refugees in a remote border jungle, the biggest gravesite of all may have been discovered hidden in plain sight.

Just 800 metres from the front door of the police centre in the Thai border town Padang Besar, and a five-minute stroll from the Thai immigration office, lie dozens of concealed graves of Rohingya refugees who have fled abject persecution in their homeland Myanmar.

More than 100 secret graves might lie in the small cemetery, and overlooking the site just metres away is the house of the smuggler believed to have put them there.

A survivor of one of the refugee jungle camps who had been press-ganged into helping the traffickers took Four Corners to the graves.

Known as Buraq, for his safety, he pointed out the graves of Rohingya friends who had died or been killed in the camps.

He said the trafficker brought the bodies off the mountain jungles and buried them in the town graveyard to avoid evidence of the dead being found at his jungle camps.

Whenever there was a load of two or three corpses, Buraq would be driven through the streets of Padang Besar at midnight towards the little-used cemetery.

No matter the threat to his life, Buraq is determined to directly accuse those he blames for the deaths of his friends and fellow Rohingyas — if there is a legal system that will listen.

Buraq describes how one friend died.

"Alom had his throat cut," Buraq said, gesturing a slash across his throat, then pointing to a nearby house.

"Slaughtered by that smuggler there."

Pedang Besar is the official crossing point between Thailand and Malaysia.

It was the heart of the traffickers' operations.

The town mayor and his deputy have recently been arrested for their involvement in the trade and a senior Thai general has been arrested on trafficking-related charges.

The scale of the trafficking network is coming to light courtesy of the detailed investigative reports by human rights researcher Matt Smith of Fortify Rights.

"None of these camps could've operated without the full awareness of the Thai authorities and also the Malaysian authorities," Mr Smith said.

"Villagers know what's happening.

"The Thai authorities know what's happening."

Watch Mark Davis's nightmarish journey along the smugglers' trail in Journey Into Hell at 8.30pm (local time) on Four Corners.