During the final stretch of construction on the Trapeang Thma Dam in 1977, on sweltering April days just before Khmer New Year, workers carried earth in shifts for 120 hours straight with only brief breaks, witness Kan Thorl told the Khmer Rouge tribunal yesterday.

Thorl, now 57, worked as deputy platoon chief at the worksite, supervising 30 workers, though he recalled 15,000 people labouring at the dam, which he said was completed in under three months – although other witness testimonies dispute this timeframe.

“At night, there were militiamen, they would monitor our movement,” he said.

To encourage the dam’s rapid progress, Thorl added that near-daily sessions for “self-criticism” and “re-education” were held, with the inefficient or those who feigned illness deprived a portion of their food rations – three cans of rice a day for a good worker.

According to the witness, between two and five members of his unit fell sick each day and less than 30 per cent were able to make their daily work quota.

“They became weaker and weaker after the food ration had been reduced,” he said.

“This was one kind of punishment imposed on us.”

The witness confirmed that these instructions were handed down by Ta Val, who oversaw the worksite; he also placed several other senior cadre members at the dam, including sector secretary Heng Rin, and Ta Cheal, a member of the sector committee.

Thorl confirmed that the control of the dam switched into the hands of Southwest Zone cadres in 1977 – “Those from the Northwest Zone were no longer there,” he said simply – but could not say how he knew this, and denied arrests occurred at the site.

In an attempt to jog his memory, however, the prosecution read a passage from Thorl’s witness statement to the investigating judges.

“One day, I saw that they had arrested people and tied them up and were walking them nearby my building during the night.

I did not know their names.

The people walking them were dressed in black and had guns slung over their shoulders so I assumed they were soldiers,” the statement read.

The proceedings concluded with the discussion of marriage at the dam worksite, an arrangement of 30 couples wed at once with minimal ceremony.

Thorl said couples chose their partners willingly, contradicting previous testimony from civil parties, and said the regime believed traditional ceremonies were excessive and that marriages only required a “resolution” between partners as they held each other’s arms.