[5] Roland Mourer and Cécile Mourer-Chauviré working for the Royal University of Phnom Penh undertook the first excavations from 1965 to 1969 and almost immediately brought to light evidence of prehistoric human occupation in Laang Spean from as long ago as 6.240 years BP.

Objects found included tools made of hornfel, pottery, burnt animal bones, carbonized matter, shells of mollusks and a great variety of micro fauna remains.

[6] In a deeper middle layer they found artifacts and tools, that "showed similarities with [] so-called Hoabinhian sites that had been uncovered in Southeast Asia, suggesting the possibility of a common cultural bedrock for a group of humans stretching from Burma to Vietnam.

The fact that some graves were lavishly adorned with stone jewelry and others not at all, suggests emergent social stratification among the population and provides researchers with "an original chronological, cultural landmark for South-East Asia, at the beginning of the Ages of Metal".

[11] The team uncovered rudimentary stone tools (chert flakes and polyhedral, multiplatform cores) in the deepest Palaeolithic levels from as far back as 71.000 years BP.