In the space of 15 seconds, four masked men wielding meat cleavers last month underlined in blood the reputation of the triads for calculated brutality and sent a shudder of speculation that the gangs are expanding their reach in Hong Kong.
When financial consultant Ben Ford was dragged out of a taxi and repeatedly hacked outside a Rugby Sevens party on March 21 - losing part of his right hand and suffering multiple chop wounds - it was the first attack of its kind on an expatriate in Hong Kong.
'It was shocking because we were crossing a line from the situation where triads fight other triads over control or finances,' said a senior police officer. 'What we had here was a totally innocent victim.
'This is stepping outside the normal code of conduct in triad societies. You don't hit expats because it draws attention to the triads and it's bad for business.'
The fact that 32-year-old Mr Ford was the victim of a case of mistaken identity - the gang had apparently been sent to attack a bouncer at the club - did nothing to lessen the impact.
'They went out knowing their target was a westerner and that is very surprising,' the police officer said.
On the face of it, the events of March 21 would appear to show a chilling confidence among Hong Kong's gangsters and a willingness to take their savagery outside their usual inter-gang feuds.