Two arrested over ex-Hells Angel's death

Thai police could charge an American man and a Thai woman over the kidnapping and murder of a former Australian Hells Angels bikie whose body was found in a shallow grave in eastern Thailand.

Wayne Rodney Schneider, 37, from NSW, was kidnapped by a group of masked men on Monday morning from his rented villa in the seaside town of Pattaya, 150km from Bangkok.

His naked, tattooed body was found about 30km away in a shallow, sandy roadside grave in Sattahip Province in Chonburi on Tuesday.

Thai police on Wednesday arrested a 21-year-old American Tyler Joseph Fulton Sheen Gerard at an immigration checkpoint as he attempted to cross into Cambodia.

Gerard was among a list of suspects wanted in connection with the kidnapping of Schneider.

Also detained was the Thai wife of 26-year old Australian man, Antonio Bagnato, who police allege masterminded the attack.

Bagnato had likely fled Thailand, immigration officials told Thai media.

But investigators told AAP Bagnato's whereabouts were still unclear.

Police located Schneider's body by tracking a rented pick-up truck through its on-board GPS system.

The Thai woman, whose name has been withheld, had rented the utility but told police she was unaware of any plan to abduct and kill Schneider.

Schneider had been living in Pattaya for about a month and shared his villa with Amad Malkoun, a former head of Australia's criminal Comancheros biker gang, police said.

Malkoun told Thai media that Schneider, Bagnato and himself had been drinking before returning to the villa ahead of Schneider's disappearance.

Thai authorities have previously drawn links between Australian bikie gangs and local drug traffickers and other illegal businesses.

The full motive for the kidnapping and murder of Schneider remains unclear.