Constable Tsui Po-ko was a serial killer whose murderous acts were unprecedented, a crime expert suggested in the Coroner's Court yesterday.

Australian criminologist Roberick Girth Broadhurst testified that Tsui had met the condition of serial killers, meaning he had made three or more killings.

Tsui was classified as a "power assertive and anger retaliatory killer", who wanted to gain self-recognition and give vent to his rage against workplace or a particular group. Tsui attempted to complete a "mission" and gain absolute control over other human beings in the killings.

Broadhurst believed, based on scientific and environmental evidence, that Tsui had killed and stolen the service revolver of constable Leung Shing-yan in 2001. Tsui had used that revolver to kill a bank security guard in 2001 and another constable Tsang Kwok-hang in last year's Tsim Sha Tsui shoot-out. Attempting to grab the constables' revolvers, Tsui also injured Sin Ka-keung seriously in the shoot-out.

Broadhurst said a serial killer would refrain from committing another crime for a certain period after the first one. But that does not mean the risk to society will be lessened as violence would be escalated from case to case.

He believed Tsui might have resorted to more reckless actions had he succeeded in seizing the revolvers of Tsang and Sin.

FBI expert James McNamara told the court that he was not aware of similar cases- a policeman killing colleagues for firearms and misleading investigation by not using the hand others know he normally uses during operations - in the database of FBI, Royal Canadian Mounted Police, and German and British police.

Serial killer cases in Hong Kong are rare. In a gruesome murder case in 1982, Lam Kor-wan, a taxi driver, killed four women and chopped off their sex organs.

Broadhurst said there should be no other criminal in the Tsim Sha Tsui shoot-out as Tsui would not find partner because he didn't have confidants. He believed Tsui did not consider buying weapons from black market as he did not trust the dealers and feared that his identity might be leaked.

Broadhurst said Tsui was a narcissist and had abnormal emotion, reflected by his calm appearance after the killings.

Broadhurst testified that Tsui had a "warrior mentality", who would always think of ways to resolve his trauma.

Broadhurst said the note found beside Tsui's bed showed Tsui believed that taking the life of the others would enable him to respond to higher calling.

"Only God can take the life of the others in spiritual sense. By taking the life of others, Tsui was putting himself on the same place as God," he said.

Tsui did not target personally at Leung, Tsang, Sin and the security guard Khan Zafar Iqbal in his operations, but he expressed contempt for the authority by hitting police constables, Broadhurst said.

Tsui's upbringing and career in the police force had undergone a series of frustrations. He failed to perform excellently at school, and was described by his colleagues as being money-conscious and polite, but secretive, self-centered and stubborn.

Tsui had also troubled family relationship as he wrote a letter to his wife in 1998, one year after his marriage, apologizing that he was "sexually active outside marriage", Broadhurst said.

The court had earlier heard that Tsui's father and brother also had strained relationship with Tsui's wife.

However, the couple still maintained their relationship because of their daughter, who was born in 2000.

Tsui also had financial problems in 1999, when he brought a luxury flat in Tung Chung as the property market plunged while interest rate had increased.

Broadhurst said it was crucial to find out what had happened to the offenders in 36 to 48 hours before they committed the crime, which he described as the "triggering events".

Tsui was criticized by his supervisor a few days before the Tsim Sha Tsui shoot-out for his handling of an arrest.

Combined with the previous frustration, the supervisor's criticism deepened Tsui's low self-esteem and trauma, which made the constable believe that decisive actions should be taken to resolve the problem.

Tsui's excellent shooting skills and knowledge of the shooting scene would facilitate his violent behaviour, Broadhurst said.

He, however, said the homicidal action would not tackle Tsui's problem, but would result in a vicious cycle as Tsui's trauma would be reinforced.

The inquest will hear the testimony of a psychiatrist, a driver of a politician and an expert who will say whether a person is left-handed today.

(HK Edition 03/30/2007 page6)