Decha said deputy police chief Pol General Ake Angsananont and his team would visit the province to follow up on the case later yesterday.
Police will ascertain if Niwat's DNA matches those collected at the scene. Decha called a meeting yesterday with 20 police officers involved in the case, and they came up with three possible motives: a robbery that turned into murder; work-related conflict; or a crime of passion.
Phayong had just moved from Phang Nga province to serve in Surat Thani in April.
Phayong's wife, Thewee, told police her husband didn't have any conflicts with anyone and he lived alone in the house. She described Niwat, who helped take care of the house, as a close friend of Phayong and they often hung out together.
Usually, Phayong would visit Thewee at her rubber plantation in Nakhon Si Thammarat during the weekends. She said she was surprised that Niwat had gone missing. Phayong's funeral will take place at Wat Pen Mit in Nakhon Si Thammarat's Chawang district.