Murder suspect Santi Supa-apiradeepailin has reversed his statement and confessed to colluding with two other Thais to kill a Thai couple in Taiwan over a drug business conflict.
The confession came after intense interrogation overnight, police said on Saturday.
Mr Santi, 35, is wanted in Taiwan for the murder of Prasert Norat, 32, and his 35-year-old wife Potjanee, who was five months pregnant with twins. The couple and the suspect were business partners.
The suspect surrendered to Crime Suppression Division (CSD) police at the 335th Border Patrol police division in Chiang Dao district of Chiang Mai around 8am on Friday. He was accompanied by his father and relatives. He was immediately taken to Bangkok.
During initial questioning on Friday, Mr Santi denied killing the couple and claimed it was the work of a Taiwanese mafia gang. Police continued interrogating him overnight and he reversed his statement.
He told police that he had plotted to kill the couple by luring them to see him, after a dispute arose over money.
He said he had bought drugs from a Taiwanese gang and given them to the couple to sell. When he asked for the money, the couple claimed they could not collect the money from customers.
Pol Col Anek Taosuparb, the deputy chief of the CSD, said on Saturday that evidence obtained from Taiwanese police showed that at least three people — Mr Santi and two associates — were involved in the murder.
Mr Santi had hired two associates to murder the couple. Surveillance camera video captured the incident, said Pol Col Anek.
The prime suspect claimed the motive was debt linked to the drug trade, said Pol Col Anek, adding that investigators were looking to see if other motives were involved.
The brother of the slain woman said earlier that the crime might have been motivated by money. He said Mr Santi had huge debts, totalling over 20 million baht, and had borrowed a large sum from Potjanee.
It was not necessary to hand over the suspect to face charges in Taiwan, said Pol Col Anek, adding that Thai and Taiwanese police would separately handle the case against Mr Santi, who is being charged in Thailand with premeditated murder. Investigators from the two countries would share information and evidence, he added.
Thai investigators have already obtained forensic evidence from the crime scene, a map showing the crime scene, surveillance video, DNA results and an arrest warrant from Taiwan that were sufficient to take legal action against the suspect, said Pol Col Anek.
CSD officers on Saturday took Mr Santi to the Criminal Court where he was ordered detained for 12 days. A criminal suspect can be detained for a maximum of seven 12-day periods, or 84 days, before a formal indictment is handed down.
Investigators opposed bail, reasoning that the killings had been brutal and the charge carries the maximum penalty.
Police told the court that the suspect had invited Prasert and Potjanee to his office on the night of June 4. When they arrived, the suspect and his accomplices beat the pair on their heads with iron bars until they died. The bodies were later put inside their BMW car.
The victims’ bodies were found in their car parked outside Taoyuan high-speed rail station near Taipei last Sunday.
Taiwanese police have examined CCTV video related to the murder and provided details to Thai authorities.
The suspect arrived in Thailand on June 9, landing at Suvarnabhumi airport, and immediately flew to Chiang Mai to visit his family in Chai Prakan district. His father later took him to surrender to police.
Investigators plan to seek court approval to issue arrest warrants for the two other accomplices.