Former tour guide Yang Yin was a foreigner who knew Singapore "very well", said the accountant who was deceived into preparing financial statements for his sham firm.

He knew how the authorities worked and what documents would be needed for a company's financial statements, she said.

The receipts, which were falsified in order to make his company Young Music and Dance Studio seem legitimate, appeared genuine.

They also contained details such as the name of the person supposedly making payments to his firm, as well as the reasons for the payments.

"Everything was in order," said the accountant in her 30s, who spoke to The Sunday Times on condition of anonymity.

"Nothing was fishy. He had all the bills, receipts, his employment pass and even a company secretary."

Yang was convicted of three cheating charges last Tuesday for dishonestly inducing the accountant to prepare financial statements based on falsified receipts made to his sham company.

The prosecution added that such acts were likely to cause damage to her reputation as an accountant.

She has a Science degree in Applied Accounting from Oxford Brookes University and became a member of international accounting body Association of Chartered Certified Accountants in 2003.

She was one of the 11 witnesses the prosecution had lined up when the hearing for Yang's case started.

Yang first approached her to prepare financial statements in 2010. Her aunt knew the former tour guide, and referred her to him.

"When he first called me asking for help, I didn't agree immediately," she said, adding that she was not paid for helping him with the statements.

"I thought about it for at least two weeks before I agreed."

Between March 1, 2010 and May 24, 2011, Yang presented the accountant receipts which included payments made to his company for piano tuition, "sound tuition" and training classes to prepare for singing competitions.

There were also bank account statements and cash deposit slips, which showed deposits made into the company's account.

Subsequently, the accountant told Yang that she did not want to help him further but he insisted.

"I was doing him a favour but, subsequently, I told him that he should look for another firm," she said.

However, Yang went back to her saying that he could not find anyone else to help him and that his accounts were simple to do.

And so she agreed to help him again with financial statements for his company dated May 27, 2013 and Aug 18, 2014.

It was only at end-2014 that she came to know of the case after the immigration authorities approached her for more information on what had happened.

"I didn't read the newspapers and didn't know about him... After ICA (the Immigration and Checkpoints Authority) approached me, I tried calling him but I couldn't locate him," she said.

In court papers, it was mentioned that had she known she had been deceived, the accountant would not have helped the 42-year-old.