'Thai Ted Bundy' arrested after woman's body found in pond at his mansion

Apichai Ongwisi, was arrested after his girlfriends body was found weight down with dumbbells and tied to a metal gate in a pond on his property. Photo / Supplied

Police in Thailand have arrested an alleged serial killer after hundreds of bones belonging to young women were found in his garden pond.

It's claimed wealthy property heir Apichai Ongwisit, 40, made his girlfriend Warinthorn Chaiyachet, 22, sleep in a metal casket to stop her leaving him.

He appears to have targeted a large number of women and killed them in a gruesome manner before attempting to dispose of their remains, with British news publication The Sun comparing the alleged killer with notorious US serial killer Ted Bundy.

Ms Chaiyachet, nicknamed Kik, was suffocated and then hurled into the pond full of carnivorous alligator gar fish at Mr Ongwisit's home in Bangkok, Thailand, last July, it is believed.

The body of the missing young woman went undiscovered until police, who had received a tip-off this month, were told she'd been murdered.

Warinthorn Chaiyachet, 22, was reported missing by her parents. Photo / Supplied.

Ms Chaiyachet's body – identified by a large fish tattoo on her back – was discovered tied to a metal gate and weight down with dumbbells in the pond on January 9.

The suspect – who has been dubbed the "metal casket killer'' – has been remanded in custody while investigators consider further charges.

Officers now believe there could be many more victims after police divers found at least 298 human bones in the water on Friday.

The family of a missing 12-year-old who lived near the property in the Thai capital's Nab Bang Khae district believe she could also be in the pond.

Police said they are hoping to drain the pond to discover the full extent of Mr Ongwisit's alleged killing spree.

In a bizarre twist, Mr Ongwisit is the son of wealthy businessman Chalermchai Ongwisit, who was jailed for butchering a 15-year-old girl in 1983 but later shot dead.

Ongwisit's mother was accused of masterminding the crime but subsequently fled abroad with his younger sister. The family owned the city's Onkvisit Market and are thought to be worth millions.

Police Colonel Jirakrit Jarunpat, commander of the Women's and Children's Welfare Division, said the investigation suggests many more victims who were killed by Apichai.

"The investigation has found several women who were involved with the culprit have disappeared. They include his friends, girlfriends and prostitutes," the police chief said.

"We have found 298 bone pieces in the pond so far but could not clarify how many humans those bones were from.

"We are also seeking his ex-girlfriend who we believe might have witnessed or have information about him killing the missing women."