Use technology if convictions are in doubt: legislator

A legislator has called for the government plan to reopen unsolved criminal cases with the use of the latest DNA technology to be expanded to check if some convicts deserve exoneration.

Leung Yiu-chung said priority should be given to those who are wrongly imprisoned.

'Victims of old, unsolved cases have waited long enough, but the prisoners are spending their life behind bars waiting. Isn't that even more unfair?' Mr Leung said he had received many letters from prisoners proclaiming their innocence, but it was one robber's case that had left the deepest impression on him.

Yue Wai-fat was jailed for life after a jury found him guilty of robbing a Taiwanese woman of a $700,000 diamond ring in Causeway Bay in 1998 and stabbing her to death during a scuffle.

'The incident happened at 4pm, but eyewitnesses prove that he was at his home in Tai Kok Tsui half an hour later. There were a lot of unanswered questions in his case.'

Mr Leung said no DNA tests had ever been performed in his case and the defendant, who lost his appeal in 2001, was not aware DNA technology could help.

Assistant government chemist Tsui Pui said any prisoners who believe they are innocent should come forward to demand a review.

'If there are voices in the community who believe the DNA technology should be reapplied to prisoners who might be wrongly convicted, we will do it.'

But the reality is old evidence may no longer be available even when the technology is there.

'If the case is still open, or there are culprits still at large, or the appeal period is not yet over, then we will keep the evidence. But if the court has convicted the defendant and everything is concluded, of course we will destroy it,' said Albert Ng Kam-wing, chief superintendent of the Crime Support Unit.

Director of Public Prosecutions Grenville Cross said in April the Department of Justice had agreed with the police that from now on - after resolving logistics issues such as the division of duties - exhibits in homicide and rape cases will be retained for 20 years in case any information emerges in the future which suggests a miscarriage of justice.

As for prisoners who want to launch a DNA review, prosecutors are given the discretion to reserve crucial evidence in some cases should they deem it appropriate.