A five-member jury Wednesday found that police constable Tsui Po-ko killed two other policemen and a security guard before being "lawfully killed" in a shootout in Tsim Sha Tsui last year.
It ended what Coroner Michael Chan Pik-kiu called the most difficult case he had encountered.
The verdict also put to rest conspiracy theories and speculation of large-scale gambling within the police force - which former commissioner of police Dick Lee Ming-kwai admitted to Shue Yan University students had affected the force's image.
After nearly 10 hours of deliberation, the three-man, two-women jury unanimously declared Tsui had unlawfully killed police constable Leung Shing-yan on March 14, 2001, at Shek To House after snatching his service revolver.
He then used that gun to kill bank guard Zafar Iqbal Khan on December 5, 2001, during a bank robbery. Tsui shot and killed constable Tsang Kwok- hang in a shootout last year.
The jury said Tsui had fired at Tsang and fellow constable Sin Ka-keung as they were patrolling the Tsim Sha Tsui underpass at 1.14am on March 17 last year. Tsang, though hit, returned fire and "lawfully killed" Tsui.
The jury produced no recommendation to prevent the recurrence of similar deaths in the future. Chan thanked Tsui's mother, Cheung Wai-mei, for her daily attendance at the inquest and expressed his condolences at the death of her son. Cheung stood up from her corner seat and twice bowed deeply to the coroner.
Solicitor Daniel Wong Kwok-tung told The Standard he will draft an opinion on the possibility of applying for a judicial review for Tsui's's mother to consider.
The coroner said Leung, Khan and Tsang all died in the line of duty. While their families only attended the inquest on occasions, he also extended his condolences to them.
Chan called it the "the most difficult" inquest for a jury he had ever encountered and, in appreciation, he said the five jurors would not be called for jury duty at a coroner's inquest for the rest of their lives. "However, I have limited authority. I cannot guarantee you will not receive a jury notice from the High Court tomorrow," he said.
Police Organized Crime and Triad Bureau chief superintendent Choy Kin- cheung said the force respected the court's decision.
"The force respects the court's findings. This is an absolutely open and transparent inquest," he said.
However, Hong Kong University law assistant professor Eric Cheung Tat-ming described the jury's findings as "unusual" and that it could lead to legal challenges. Cheung said according to the Hong Kong Coroners Ordinance, an inquest is held to determine when, where and how the death came about and not who killed who.
He said in recent years the European Court of Human Rights and the British House of Lords had expanded the role of a coroner's inquest and consequently the ordinance in Hong Kong might have to be reviewed and amended in future.
Dennis Wong Sing-wing, associate professor at the department of Applied Social Studies at the City University of Hong Kong, said the findings were comprehensive and different from other inquests, where only the cause of death would be determined.
Wong also stressed the importance of psychological screening for future police recruits.
"Aptitude tests in police entry exams are only one of the tools. Tsui was fine when he joined the police. Such a test would not screen out frustration on the job later on." He said the promotion system in the force now was not sufficiently transparent and should be reviewed.
Officers who keep failing promotion tests could be brewing time bombs, he added.
Wong suggested the force should pay more attention to officers who are talented but fail to rise up the ranks. He also suggested the force should have independent psychological counseling services so troubled officers can seek help without fear.
He said many criminals were like Tsui, who did not know how to face frustration, choosing instead to take an illegal path in obtaining socially approved goals, such as money, prestige or status.
"All criminals are like this. In my eyes, Tsui was only one of them. He was aggravated, frustrated and trying to gain prestige inside his head," Wong said.
According to a police spokesman, there are no personality tests during recruitment and the promotion selection process.
The force is, however, monitoring overseas experience in employing psychometric tests during the recruitment process, he said.
Secretary for Security Ambrose Lee Siu-kwong said he respected the verdict. He said the police would not conduct further investigations on the three cases following the coroner's findings.
A police spokeswoman said the death gratuities payable to the two constables killed in the line of duty would be calculated in accordance with the relevant pensions legislation.
She said Tsui was not eligible as he was not on duty, nor was he executing constabulary duties when he was killed.
Assistant Commissioner of Police Lo Yik-kee said the verdicts of the jury matched the results of the police investigation.