“We will distribute the documents to the media by tomorrow, in line with my father’s wishes,” Pol Lt-Colonel Hemachak Bunnag, the youngest son of former deputy national police commissioner Pol General Salang Bunnag, said on Monday.

Salang left a suicide note expressing his opposition to double-track railways projects and voicing suspicion about other development plans. He killed himself by jumping from the seventh floor of a shopping complex in Nonthaburi.

Hemachak said Salang had been fighting against one-metre, double-track railways for four decades. One-metre rail is considered narrow gauge and is cheaper to construct than wider gauge networks.

“Over time, he developed stress and depression,” he said.

Bathing rites for Salang will be held at the Debsirin Temple in Bangkok on Monday.