Law enforcement officers from Taiwan can accompany murder suspect Chan Tong-kai back to the island as long as they have his consent and do not exercise their legal power while in Hong Kong, experts say. But critics fear unofficial tactics for transferring a suspect such as these could spark concerns about agents from mainland China doing the same, given past incidents where booksellers and a Chinese tycoon disappeared only to later emerge in custody across the border. Chan, 20, was released from Pik Uk Correctional Institution in Clear Water Bay on Wednesday after spending 19 months in custody on money-laundering charges. He is wanted in Taiwan for the murder of his pregnant girlfriend Poon Hiu-wing, 20, in February last year while they were on a trip there. Despite admitting to the crime in a Hong Kong court, he cannot be tried for murder in the city because the killing took place in Taiwan. He pleaded guilty to money-laundering charges stemming from his use of the victim’s money after he fled home to Hong Kong. His case sparked the biggest crisis in decades for the Hong Kong government when it tried to push through an unpopular extradition bill, which would have allowed the transfer of suspects to jurisdictions with which the city has no agreement, including Taiwan and mainland China. The bill was formally withdrawn on Wednesday. Over the past few days, the case also sparked a row between Hong Kong and Taipei as the sides tangled over how Chan, who intended to turn himself in to the Taiwanese authorities, could be handled. Taiwan offered to send officers to pick up the suspect, a suggestion dismissed by the Hong Kong government as “ totally unacceptable ” and “a disrespect” of the city’s jurisdictional power. Why a murder case row is giving Tsai Ing-wen an election edge While Taiwan’s Mainland Affairs Council said it sent Hong Kong a letter expressing its intention to bring Chan back, the island’s president Tsai Ing-wen wrote in a Facebook post that officers would “escort” him. How it might work depended on what the officers intended to do, experts said. Barrister Ronny Tong Ka-wah said it would not be possible if they wanted to escort Chan by exercising their power in Hong Kong. “No jurisdiction will allow another jurisdiction to enforce the law on its own turf,” said Tong, a member of the Hong Kong leader’s top advisory body the Executive Council. But University of Hong Kong legal scholar Simon Young Ngai-man said that since Chan was a free man, he could choose with whom he travelled back to Taiwan. “If the Taiwanese officers were to come to Hong Kong only to accompany him back, without purporting to exercise enforcement jurisdiction, in theory this is possible as long as Chan consents,” he said, although the government might be sceptical of the officers’ claim and deny them entry. Hong Kong authorities perceived such an attempt as “escorting”. The exact wording Taiwan authorities used in the letter has not been made known. Will murder suspect’s return to Taiwan end Hong Kong’s violence? There was also a political dimension, as Young said Hong Kong might also need Beijing’s approval when handling official matters with Taiwan. A source from Taiwan’s Criminal Investigation Department admitted the situation had changed, and that it would be legally impossible to send in officers since Chan was now a free man. “But if he wants to turn himself in to police, he can apply for a visa to come to Taiwan and board a Taiwan carrier where we will send an officer to escort him back to stand trial,” the source said. The island’s interior ministry also said Chan was on an immigration control list, and once he applied for a visa and boarded a flight to land in Taiwan, he would be arrested. Professor Zhao Yun, an international law specialist at HKU, said if Chan boarded a plane chartered in Taiwan, then Taiwanese officers could already have jurisdiction and arrest Chan even at Hong Kong airport. “The jet bridge would already be deemed as an extension of Taiwan’s sovereign territory, before the plane even took off,” Zhao said. Some have drawn parallels between Chan’s case and one in 2016, when nine Hong Kong police officers flew to Taiwan to accompany three murder suspects back in a deportation arrangement made possible by unofficial communications between authorities. Hong Kong was told the details of the suspects’ flight so officers bought seats near them and arrested them upon landing. Don’t put politics before justice, Hong Kong urges Taiwan over fugitive case A government source noted a subtle difference, saying the trio were expelled by Taiwan authorities, who were empowered to impose coercive measures on them. “But Chan is a free man after he walked free on Wednesday,” he said. Former Hong Kong security minister Regina Ip Lau Suk-yee said that if Taiwanese officers could be allowed to collect evidence in the city, then so could ones from the mainland. Young agreed, saying such concerns were valid as mainland agents could well undertake similar missions. But Democratic Party lawmaker James To Kun-sun suggested the arrangement could be done fairly if Hong Kong police followed the Taiwanese officers to make sure Chan’s rights were protected and that he could pull out if he changed his mind. The Taiwan side had also floated the need to establish a formal mutual legal help agreement so it could obtain Chan’s admission in the Hong Kong court. But Hong Kong’s Mutual Legal Assistance in Criminal Matters Ordinance states the city can only set up those arrangements with a jurisdiction other than the “central people’s government or the government of any other part of the People’s Republic of China”. An agreement between Taiwan and Hong Kong is bound to be controversial. While Taiwan is a self-ruled island, Beijing considers it as a wayward province. Hong Kong’s Security Bureau said it would not comment on whether it was the cause of its apparent reluctance to strike a deal. Another government source said Hong Kong police could not hand over Chan’s court testimonies to Taiwanese authorities because of the lack of a legal help agreement. Police would have to discuss with them the way forward due to the complications involved, he said. Taipei-based human rights lawyer Lucas Wang Lung-kuan said that if Chan was willing to cooperate, it did not matter. “Taiwan’s prosecutors can conduct another inquiry, and use the confession conducted in Taiwan,” Wang said. Secretary for Justice Teresa Cheng Yeuk-wah said Chan was free to provide them with the materials while the Hong Kong government would try to provide help. Additional reporting by Gary Cheung and Christy Leung