Police on Friday arrested a 47-year-old woman who was implicated as conspiring with her 36-year-old plantation worker lover in the murder of her 56-year-old plantation owner husband in Kanchanaburi's Sai Yok district in August 2015.
Supatchaya Sirisuk was arrested in Muang Kanchanaburi under a warrant issued on Thursday.
Earlier this week her alleged lover, Phuphathong Phathongphum, was arrested along with his four accomplices - two Thai men Natthapol Wiwatkulthorn, 27, and Montri Soonkham, 22, and two Burmese men Zho Nee and Kniew Ong, both 25.
Phuphathong then reportedly confessed to plotting the murder of Nawapong Sajjathampiwat.
He claimed that the victim had put a black-magic curse on him following an argument over the discovery of his wife's affair with Phuphathong.
The murder suspect denied the motive of wanting to take over the victim's property and run off with his wife.
A police source said that following Nawapong's disappearance in August 2015, Supatchaya told her three children that their father had moved to Myanmar to be ordained as a monk.
Then Supatchaya and the children moved in with Phuphathong in Thong Pha Phum district, while the four workers moved away.
Following her arrest, Supatchaya reportedly made a partial confession by admitting she had an affair with Phuphathong and she knew about Phuphathong's plan "to assault" her late husband.
She claimed the suspect told her in July 2015 that he would assault Nawapong to cripple him but that turned into a murder and she did not know what to do so she kept quiet.
A police source said that the case came to police's attention after Nawapong's 21-year-old son became suspicious about his father's disappearance.