The DNA sample on the surgical mask found near the body of dead constable Leung Shing-yan six years ago matched with the DNA samples of Tsui Po-ko, it was revealed in the High Court yesterday.

The information was revealed when High Court judge Michael Hartmann rejected a judicial review application by Tsui's mother Cheung Wai-mei asking for a separate death inquest of Leung, Pakistani security guard Khan Zafar Iqbal, Tsui and another constable Tsang Kwok-hang, being held concurrently now in the Coroner's Court.

Leung was gunned down on March 14, 2001, when he went to investigate a bogus noise complaint in Shek Wai Kok Estate. His service revolver was also stolen. That revolver was believed to be used to kill Khan in a bank robbery on December 5, 2001, and constable Tsang in last year Tsim Sha Tsui shoot-out. Tsui was killed by Tsang's revolver.

Cheung's application stated that Leung's service revolver was found under the body of Tsui at the Tsim Sha Tsui shoot-out scene on March 17, 2006; and the DNA sample found on the surgical mask found near Leung's body matched with Tsui's.

"Subsequent forensic investigation, by matching the DNA samples obtained from bloodstained mask found at scene A (Shek Wai Kok Estate) in year 2001 with the DNA profile of Tsui, suggested that Tsui could be one of the contributors of DNA samples found on the mask," it said.

Presenting the argument to Justice Hartmann, Cheung's barrister Arthur Yip said it was feared that the jurors might be prejudiced under the concurrent inquest as they might be influenced by the evidence of Leung and Khan's cases when handling Tsui's death.

Justice Hartmann said there was no restriction for the media reporting yesterday's hearing.

He, however, said coroner Chan had the discretion to decide how best to manage the hearing.

Meanwhile, the Coroner's Court was told that the killer-robber in the Hang Seng Bank heist in 2001, linked to the mysterious killings of three police constables, had threatened that he had a bomb.

The bank branch manager, Au Lai-ching testified yesterday that the suspect, also in dark green hood, had fired three shots. The first two shots were fired at Khan, standing seven feet from the suspect. Au only heard the sound of the third shot as she had squatted hiding under the table.

Au had reported the incident to police hotline 999, but the operator could not hear her message and asked her to repeat. She also pressed the branch alarm, which was connected to the bank's headquarters in Central.

"The man had already jumped over the counter (No 4) when I hung up the phone. He told me not to move as he had threatened he had bomb," she said.

Au said she called up the police hotline fearing that they would be taken hostage.

The man proceeded to counter 7 after taking the money from counter four and keeping it in his black bag. He then got back to counter two and three before leaving the bank.

Fong Sau-ying, a bank staff working at counter 7, said the suspect had white glove and might be wearing his windbreaker inside out.

Fong saw flashes of light coming from the suspect's gun when two shots were fired, and she squatted down after seeing Khan slumping down to the floor.

"The man was taking away the money from the drawer on top of my head. The man told me not to look at him, or else I would be shot. I was terrified and hid myself in the cabinet under the drawer," she said.

Both Au and Fong said the suspect was about six feet tall, about the same height as Khan.

One of the bank's closed-circuit TVs video played back in court on Thursday showed that the operation of the killer-robber lasted less than 80 seconds.

But the video did not show the suspect firing the shots. That image was recorded by the bank's still camera, which would be presented to the court next week.