The daughter of missing businessman Chaichana Mai-ngan has lodged a complaint with the Crime Suppression Division (CSD) and offered a 1-million-baht reward for information on her father's whereabouts.
Chatthip Mai-ngan filed the formal complaint yesterday after her father went missing, presumed kidnapped, on July 1.
She said she was deeply concerned about her father's well-being and made an emotional plea for his release.
"I beg of you to release him," she said, adding her father suffers from diabetes and high blood pressure and needs daily medication.
Mr Chaichana, 67, a clothing merchant at Rong Kluea market in Sa Kaeo's Aranyaprathet district, vanished while driving to buy groceries from the market in his white Nissan Navara on Monday. A security camera later captured images of his vehicle in Prachin Buri's Kabin Buri district.
CSD deputy chief Prasopchoke Prommul said the circumstances of Mr Chaichana's disappearance remained unclear. However, investigators were giving weight to a land deal Mr Chaichana was involved in as a possible motive.
Ms Chatthip offered a 1-million-baht reward for anyone who provides clues to her father's whereabouts.
Mr Chaichana's other daughter, Sapsakul, said earlier her father was engaged in a legal battle over a plot of land near the Thai-Cambodian border.
He was also involved in various court cases with government officials and local figures.
Mr Chaichana is also a key supporter of the anti-government People's Alliance for Democracy.