Widely considered the "King of Khmer music," Sin Sisamouth, along with Ros Sereysothea, Pan Ron, Mao Sareth and other Khmer artists, was part of a thriving pop music scene in Phnom Penh that blended elements of Khmer traditional music with the sounds of rhythm and blues and rock and roll to make a Westernized sound akin to psychedelic or garage rock. Sisamouth died during the Khmer Rouge regime under circumstances that are unclear.
https://en.wikipedia.org/wiki/Sinn_Sisamouth