Then, Sept15 came.

At DBS Bank, top executives spent the day looking at documents and trying to figure out what Lehman's demise meant, then drafting letters to its High Notes investors, building up FAQs for its relationship managers, and calling for an emergency meeting with them.

On Sept16, stock markets in Japan, Hong Kong, China and South Korea dived as anxious investors reeled from the carnage.

A week later, DBS Bank started an Investor Care Centre (ICC) headed by senior managers. It took care of mounting complaints about mis-selling and other grievances. It has received more than 300 complaints so far.

Some meetings with investors were civil enough, while others exploded into confrontation. One investor recounted how his meeting with a senior employee of the bank on Sept30 degenerated into a staring match.

'I felt badgered. They were butting in and cutting you off in mid-sentence. Many people found them very belligerent. Someone told an investor to go fly a kite,' said another investor who met the team.

Mr Raju, who has also spent the last month talking to affected customers at their homes or offices, is aware of such complaints.

'There have been cases where clients came back and told us that the ICC officer was not polite, or was there to defend the bank, etc,' he said.

'In my mind, I'm very clear that the bank values integrity, and if a client feels he has not been heard, not a problem. We'll get someone else to hear him out. That's what we're here for.'

Over the days, Minibond and High Notes investors started receiving calls from their relationship managers who told them to brace themselves for a big hit to their wallets.

Desperate and angry at the same time, many cried foul, charging their relationship managers with misrepresentation and criticising the banks for putting out risky products to retail investors, many of whom were financially clueless.

Minibond investors wasted no time in organising themselves. On Sept24, some 200 gathered at the National Library to sign a petition which was given to the Monetary Authority of Singapore (MAS).

Up until then, the central bank had been measured - some would say too hands-off - in its approach to the Lehman debacle.

On Sept22, a week after Lehman's crash, the regulator finally spoke up, asking banks and finance companies to make it a priority to deal with affected investors, and telling investors to go straight to their banks with their complaints.

Two days later, it took a more pro-active stance by ordering financial institutions to appoint an independent party to investigate complaints of mis-selling after similar accusations began to surface.

The gripping daily headlines disturbed one person greatly.

Former NTUC Income chief executive officer Tan Kin Lian has never been a fan of structured products, but he had no idea so many people were mired in it.

'I believe there is something seriously wrong with the creation and marketing of these products, and that there is some possible wrongdoing,' he told The Sunday Times.

He organised two petitions to pressure the authorities to investigate and rallied more than 500 investors at Speakers' Corner last Saturday and again yesterday, to cheers.

'I consider it to be a public duty. If I find that there is something wrong and so many people are affected so badly, it is my responsibility as a citizen to help them to find redress,' he said.

'I am angry that these structured products were allowed to be marketed to retail investors and that they were pushed by the financial institutions which had the responsibility to make the appropriate recommendation to the retail investors,' he said.

Investors and netizens hailed Mr Tan as a national hero, but his comeback was: 'I understand from history that many heroes died in the battle. I hope that I can survive and live to an older age.'

He has also encouraged disgruntled investors to lodge complaints with their banks.

On Friday, MAS made its strongest stance yet on the case when it called on the financial institutions to 'do the right thing' and take special care of lowly educated retiree investors during their investigations into their complaints.

It also told banks not to take an 'overly legalistic' approach when dealing with such cases.

Asked what he hopes to see happen, Mr Tan said: 'I hope that there can be a fair settlement. I hope that the financial institutions will offer to compensate the investors for 50 to 80per cent of their loss.'

Among the hundreds who gathered for the Speakers' Corner rally on Oct11 was Ms Lin Ling, 37, a China-born Singaporean who was persuaded to move $60,000 from her fixed deposit into Minibonds in July this year.

'I haven't slept well or eaten well for the past few weeks,' the part-time worker and mother of two young children said in Mandarin.

'The Chinese have always thought the best of Singapore. Now, the behaviour of these financial institutions has completely destroyed this impression. I want them to give me back my money,' she said angrily.

Perhaps buoyed by the investor activism since the episode began, a small group of frustrated investors planned a gathering outside DBS' Shenton Way headquarters last Wednesday to seek out the bank's senior management.

Their plan, however, was foiled when the police got wind of it and issued a warning that it would be illegal.

In the end, only 11 investors showed up at DBS' door. The bank was expecting them: It deployed a band of staff members armed with refreshments and welcomed them into its auditorium to meet Mr Raju and his team.

They were not alone. Marked police patrol cars and even policemen on foot were circling the buildings. Several other men, dressed in casual T-shirts and jeans but believed to be plainclothes officers, were also trying to blend into the landscape.

One investor and his wife, both retirees, said they had gone there to voice their anger at being misled into buying DBS High Notes5.

'I paid $100,000 to learn a new word called 'credit event',' he said bitterly.

'It's already so embarrassing, so please don't take my picture or quote my name,' he said as he and his wife were leaving the auditorium.

Mr Raju said DBS would take responsibility if there had indeed been cases of mis-selling, which means possibly compensating such aggrieved investors.

He said one question he asked his relationship managers at the townhall meeting was: 'Are you sure you sold it the right way?'

'At the end of the day, it's a discussion between the relationship manager and the customer. I got a 'yes' consistently. And that gave me some comfort.'

High Notes5 was sold at selected DBS branches and never made available at POSB branches since it was targeted at a more sophisticated, affluent audience, he said.

It needed a minimum of $25,000 to participate, while Minibonds were sold at a minimum of $5,000.