Plans by Hong Kong to allow extraditions to Taiwan, Macau and mainland China following a high-profile murder case could become a "Trojan horse" for Beijing to pursue critics, pro-democracy lawmakers warned Wednesday.
The financial hub's Security Bureau has proposed changing the law in the wake of the murder of Poon Hui-wing, a pregnant 20-year-old Hong Konger allegedly strangled by her boyfriend during a Valentine's holiday in Taiwan a year ago.
Poon's body was found dumped on the outskirts of Taipei after her boyfriend Chan Tong-kai returned home to Hong Kong without her.
Chan is currently facing trial in Hong Kong for theft and money laundering linked to his alleged possession of Poon's bank card. 
But there is currently no prospect of him being extradited to Taiwan where he is wanted for murder. 
Despite being part of China since its 1997 handover, semi-autonomous Hong Kong still has no extradition agreement with Macau, Beijing or Taipei.
The city laws governing extraditions currently rule out returns to "other parts of the People's Republic of China". Like Beijing, Hong Kong views Taiwan as a part of the mainland, which hobbles its ability to coordinate with Taiwanese police.
In a briefing paper to the city's largely pro-Beijing legislature, which will debate the proposals on Friday, the Security Bureau said the Taiwan case showed that current extradition laws "must be amended promptly to plug their loopholes and to protect public safety".
The bureau has proposed allowing extraditions on a "case-basis" and say prosecutions based on "race, religion, nationality or political opinions" would be refused. 
But prominent pro-democracy lawmakers fear the move could still allow Beijing to tighten the noose on critics.
"We're terribly worried. This could prove a Trojan horse," lawmaker Claudia Mo told AFP.
"I know the Hong Kong government has implied that political cases will not be entertained, but we all know Beijing could always package ideological crimes in the form of economic offenses."
China has a long history on pursuing critics with fraud and other crimes -- dissident artist Ai Weiwei was famously prosecuted for tax evasion.
Pro-democracy lawmaker Eddie Chu warned the proposal could "open Pandora's box". 
"The Security Bureau's proposal has far-reaching consequences and must not be casually accepted," he wrote on Facebook.
Although the proposal has been backed by the city's largest pro-Beijing party, pro-democracy lawmakers say Hong Kong should pursue a separate extradition agreement with Taiwan that doesn't include the mainland.
Historically Hong Kong has balked at extraditing to the mainland because of the opacity of China's criminal justice system and the death penalty.
The city was also rattled in recent years by the disappearance of several booksellers who resurfaced in China facing charges -- and the alleged rendition of billionaire businessman Xiao Jianhua in 2017. 
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