The inquest heard that shoot-out victim constable Tsui Po-ko had probably suffered from schizotypal personality disorder, having seven out of the nine symptoms. It also was said Tsui resorted to committing criminal behaviour to satisfy his thirst for excitement, which he found absent from his police career.
FBI official James McNamara analyses Tsui's personality and based his assessment on the police interview statements taken from the constable's colleagues and friends. He said Tsui did not want to - and did not feel the need to - establish relationships with people.
His sole source of success seemed to have come from his promotion in career, he said.
'He was frustrated when the senior officers asked him to work more on crime prevention instead of giving out fine tickets.'
It was said Tsui liked seeking excitement and it was acted out by allegedly ambushing the police officers, robbing a bank in broad daylight and executing a bank security guard.
'The excitement which was absent in his position as a police constable may have been found in his carrying out of the criminal acts.'
Mr McNamara cited some behaviour of Tsui, as recounted by his colleagues and classmates in training school, saying it was odd and eccentric.
'His peers in the police training school saw him taking the target paper with which he used to practise shooting back to the dormitory and was admiring it. They found it really strange.'
'He used to cross the border for prostitutes with a small group of colleagues. But the colleagues preferred not to travel with him after seeing him chant anti-communist slogans to the army guards stationed there. His behaviour worried the others. They found it odd and risky.'
The inquest continues hearing expert evidence on the crime analysis of Tsui.
Witnesses: FBI official James McNamara and clinical psychologist Ephraem Tsui Pui-wan.