She said Mr Prakarn came to her house on Wednesday night to have some shirts screen-printed and to have a drink with her husband in the living room.
After about an hour, Mrs Jaruvan put her child to bed and went to check on her husband. She found him lying on the floor in a pool of blood and Mr Prakarn had gone.
Police believe the two men argued while they were drinking, which led to Samong's death.
Officers are searching for Mr Prakarn.
On Friday, a Facebook user calling himself Maleficent Meditation, whom police believe to be Mr Prakarn, wrote on his Facebook page that he had killed the singer.
The gruesome pictures he posted of the crime scene had 450 "Likes" as of Saturday afternoon.
"I have intended to end my life since I was 25. Because I'll die eventually, I want to drag down those who tarnish Satanism with me. But I refrained from killing women and children," he wrote.
"In my view, I have more respect for devoted Buddhists, Christians and Muslims than those who call themselves Satanists without knowing anything about it," he wrote. "If I did not kill him, I'm sure he would be murdered by someone else later."