He said speedier law enforcement action could have been possible in transferring the fugitives in this case had Hong Kong police also requested help from Taiwan’s immigration agency instead of only contacting the island’s police force.

A spokesman for Taiwan’s National Police Agency said it was merely enforcing immigration laws in this case and refused to elaborate.

Taiwan no ‘typhoon shelter’ for body-in-cement murder suspects: Hong Kong police bring back trio

The unofficial transfer of fugitives on Tuesday was the first coordinated law enforcement effort of its kind between the two sides since the 1997 handover.

Despite the existence of a mutual legal assistance agreement between Taiwan and the mainland on matters such as joint law enforcement efforts, intelligence exchanges, transfer of people convicted of criminal offences on either side of the Taiwan Strait or the recognition of civil or mediation rulings, no similar agreements have been signed between Hong Kong and Taiwan.

Commenting on what the mainland-Taiwan agreement had achieved since coming into effect in 2009, President Ma Ying-jeou said last year that both sides had cracked 81 per cent of the 67,000 cases the two sides worked on together, and brought about the transfer of more than 6,000 suspects.

Meanwhile, Taiwan authorities have imposed a life ban on the three male suspects sent back to Hong Kong on Tuesday night from returning.

Breakthrough in body-in-cement murder case: Taiwan sends back three wanted Hongkongers

The men – aged 20, 23 and 26 – were accused of fleeing Hong Kong after the decomposing remains of Cheung Man-li, 28, were discovered inside a cement-filled box in a Tsuen Wan building last month.

But the fourth and only female suspect who also fled to the island would not be added to the blacklist nor would she be banned from entering Taiwan for a specific period, Hsu said.

It was the information the female suspect, 18, provided to Taiwan police that led officers to the three other suspects. The woman asked for police protection saying she feared for her life if she remained with the three any longer.

She claimed she was the least involved in the murder case and that she intended to assist with the investigation, according to Taiwan police..

The four suspects were arrested by Hong Kong police on suspicion of conspiracy to commit murder as soon as they returned from Taiwan on Monday and Tuesday.

At about 3pm on Wednesday, the 18-year-old woman, who was hooded and handcuffed, was escorted by police to the scene of the crime in Fui Yiu Kok Street, Tsuen Wan. The 45-minute re-enactment ended at about 3.45pm.

In the evening, she was charged with conspiracy to commit murder. The woman will appear in Tsuen Wan Court on Thursday.

Meanwhile, in a reply to the Post’s inquiries, the Security Bureau said: “In combating crimes, law enforcement agencies in Hong Kong maintain close co-operation and liaison with their counterparts in other jurisdictions in the exchange of intelligence and experience from time to time.”

James To Kun-sun, a solicitor and Democratic Party legislator, said it was possible for Hong Kong and Taiwan to create a formal mechanism on the ­transfer of fugitives.

“Of course, the first condition is that Hong Kong can get the nod from Beijing,” To said.

“There is already a precedent. And the systems of Hong Kong and Taiwan are more or less the same.

“We can specify in the agreement that transfers would not take place in political cases or those which might involve danger to national security. That should make it easier.”

But the lawmaker said he ­appreciated it would be difficult from a political point of view, especially when Taiwan would soon have a new president.