Two very different cases of fugitives being brought to justice illustrate growing police and judicial co-operation between China and other countries. China had to fight for 11 years for the extradition of criminal mastermind Lai Changxing before a Canadian court finally accepted assurances that he would not be executed. By contrast New Zealand readily accepted the same assurance before handing over a case of a killing by a Chinese national on its own soil to Shanghai prosecutors.

One man fled China to escape justice; the other sought refuge from justice in China, which has no extradition treaty with New Zealand. But Shanghai native Xiao Zhen, who stabbed an Indian taxi driver to death in Auckland in January last year in a dispute over the fare, went on trial for murder in Shanghai this month because China maintains extraterritorial jurisdiction over its citizens. That is to say, it can try them for offences committed anywhere in the world.

What sets the New Zealand matter apart is the level of co-operation with the Chinese authorities over 17 months, culminating in the appearance at the trial of the Auckland detective in charge of the investigation, who brought evidence for use by the Shanghai prosecutors. As a result it is coming to be viewed as a test case for China to show that it can be fair and that promises will be kept, especially in the light of international interest in the Lai trial when it happens. Neither Canada nor New Zealand sanctions the death penalty or was willing to co-operate with the Chinese authorities without formal assurances that it would not be applied. Canada's reticence was understandable, given that the roundup of Lai's network of associates and corrupt officials resulted in 14 death sentences and eight executions. But there is no reason to suppose that China will not honour its promises. To do otherwise would seriously damage bilateral relations and undermine its international credibility.