In the eyes of the self-employed dealers who attended the meeting at the Financial Services Authority's headquarters at Canary Wharf, in London's Docklands, Ho Park's "offence" was quite simple: he had lost their money.
Betting on financial futures, the Cambridge graduate had gambled on the rise and fall of the German government bond market. He seriously misjudged, and over two frantic days shortly before Christmas he lost a not-so-cool pounds 6.2m - money which belonged to other traders and, crucially, money which he could not repay.
"We are the fall guys in all of this. Why is it the small guys who have lost out?" asked one angry trader at yesterday's heated meeting at which regulators were jeered and heckled.
"Are the Serious Fraud Squad going to be called in to investigate?" demanded another of the traders, who have each lost between pounds 15,000 and pounds 1m.
Ever since New Year's Eve, when The Independent revealed the identity of the trader whose actions led to the closure of Griffin Trading Company - a sizeable Chicago-based trading house - and GLH (Derivatives) Ltd, Ho Park, 27, has been in hiding.
Though he has been in daily contact with his family, his lawyers and one or two business associates, there has been no sign of Ho Park at his home in London's upmarket Eaton Place. Likewise, there have been few clues as to his whereabouts at his mother's house in Esher, Surrey, where the curtains remain drawn and telephone messages are not returned.
There was speculation that after leaving his flat on 30 December last year, he and his girlfriend Charlotte Curling, a kindergarten teacher, had gone overseas. But after Ho Park's dramatic but brief appearance yesterday morning, having been tracked down by the media, it was clear he had spent what must have been a very unfestive festive season in Britain.
One can only guess what has been going through his mind. While the FSA said earlier this week that those traders who had lost money could expect to recover 50 per cent of their losses, the Serious Fraud Squad could yet be called in if there is any evidence Ho Park committed a crime rather than just an expensive error.
"If we discover any evidence of criminal misconduct we shall pass it on to the relevant authorities," Michael Folgar, of the FSA, told traders.
The liquidator, Finbarr O'Connell, of accountants Grant Thornton, has said he will be meeting Ho Park for a full and frank discussion "within the next couple of days".
Ho Park's mistake is small beer compared with the pounds 860m lost in 1995 by Nick Leeson trading in Singapore, yet there are similarities between the two traders. Both gambled on notoriously volatile futures markets, both breached trading limits and both apparently allowed one initial mistake to spiral out of control.
Both also seemed unlikely rogues of the Square Mile. Ho Park, the New York-born son of a Korean millionaire, is widely considered to be a hard- working, ambitious young man, prepared to put in the hours to succeed.
After graduating from Trinity College, Cambridge, Ho Park joined the American investment bank Credit Suisse First Boston, where he spent five years before leaving last year to set up as a trader on his own account.
After leaving the company, he continued trying to gain further experience, enrolling at the highly respected London Business School, where he remains a student on the part-time Masters in Finance programme. (Perhaps crucially, while Ho Park had completed the first part of the 21-month course which deals with accounting, he had not yet started the section that covers derivatives - the complex financial instruments on which he lost the millions.)
"He usually leaves his house before 6am in the morning and is not back until very late in the evening," said one of his neighbours, Jose Ferriera.
"He and his girlfriend are the sort of people who keep themselves to themselves. I don't think they go out very often to bars or restaurants. They occasionally have people around but not very often.
"He seems like a hard-working young man who wants to get on in life."
Friends and associates from Cambridge, from where he graduated in 1993 with a BA in Mathematics, remember a pleasant, quiet man with a goatee beard and an earring.
"I couldn't believe it when I read about John in the papers. It is not the sort of thing you would have expected of him," said one friend, who asked not to be named.
Another said: "He was the sort of person who always seemed to keep a pretty low profile when he was at college. To be honest, I am shocked and I know his closest are even more so."
David Curling, the father of Ho Park's girlfriend and a director of City stockbrokers Williams de Broe, was even more blunt: "There has been a lot of rubbish written about him and I am sure that those people who have been writing it will be hearing from the lawyers very soon."
That is, if his creditors do not get to him first. The mood at yesterday's FSA meeting was ugly. While those traders will get some money back over the next couple of months, the nature of the way in which they operate means that without this capital they cannot work.
In order to trade, individuals need to be able to prove to regulators that they have the cash to cover their costs. To do this traders have to place money on deposit with a recognised firm, such as Griffin. What has come as a shock to traders was that Griffin put their money into one central pot and that - through an apparent loophole - Ho Park was able to use their money to fund his trading.
Envy may be another factor. Traders are clearly angry that while many had lost money they had raised themselves, Ho Park, who drives a new BMW and whose trademark jeans and trainers belie his wealth, was using money which he had been given by his father, the Korean millionaire Young Ho Park.
Bars and pubs in the City have been buzzing this week with talk of an pounds 18m trust fund set up by Ho Park's father - who still lives in Seoul - for his son.
"Why have we lost out while Park has become a rich boy?" asked one.
Other traders have criticised what they describe as the casual way in which Ho Park reacted to his disastrous loss.
"I was in the offices the morning the news came through and it was announced that we were basically dead and buried," said one Griffin employee who worked from the building where Ho Park had an office.
"Park walked into the lounge to get a cup of water. He did not look stressed. I knew that he knew what I knew. I remember looking him in the eyes and thinking to myself, `what a prat'. I remember the expression on his face - he was not fazed at all by what had happened."
Over the next few days, Ho Park will be forced to explain himself - both to the regulators and to the wider trading community. He was said last night to be feeling surprised at the way events had turned.
"He is speaking to his solicitors," said his girlfriend's father. "It has come as a thunderbolt to me and a thunderbolt to the lawyers."
Thunderbolts or not, there is real anger amongst those traders who make their living risking all on the vagaries of the markets. One trader who rang The Independent said: "You know why the traders have not revealed where Park is and why he has been able to stay hidden for so long? It is because we know what you will do - you'll give him a chance to have his say. All we want to do is to cut his throat."
It is clear that early morning tears and apologies, however sincerely meant, are not going to be enough.
Additional reporting by John WillcocksReuse content