SINGAPORE - Yang Yin, the former tour guide from China who was convicted of cheating a rich Singaporean widow of $1.1 million, will serve a longer jail term of nine years.

Yang, 42, was convicted in September last year for two offences of criminal breach of trust and sentenced to six years in jail. He had misappropriated the money from Madam Chung Khin Chun, now 90, in 2010 and 2012.

On Friday (March 3), the High Court extended the jail term to nine years on grounds that the initial sentence imposed by the State Courts on the Chinese national was manifestly inadequate.

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In his oral judgement, Judge of Appeal Tay Yong Kwang said that original six-year jail term did not "reflect adequately the abhorrent nature of the accused's conduct leading to the offences and after they were uncovered".

The Attorney-General's Chambers (AGC) had appealed for a longer jail term of 10 to 11 years.

Justice Tay said that general deterrence has to be the main sentencing principle in the case.

"In every society, taking advantage of vulnerable persons in the community is completely unacceptable and utterly reprehensible.

It must be denounced and deterred by sentences that reflect this sentiment in clear and strong terms," he said.

He did not mince his words, noting that Yang had "claimed audaciously and shamelessly that he was a caring man looking after the needs of the victim as though she were his grandmother".

In reality, Justice Tay said, Yang had "eased his way smoothly, cunningly and methodically" into the victim's life over time to siphon off her assets.

The two crimes that he admitted to, Justice Tay added, was part of an "elaborate scheme encompassing practically all the earthly possessions of Madam Chung", including her sprawling bungalow.

Had he succeeded, the assets that he siphoned off "would have elevated him to such heights of wealth that he probably would not need to work for the rest of his life", Justice Tay said.

"In all likelihood, the accused would have become a millionaire many times over if he had not been exposed by the victim's niece," he added.

Justice Tay had heard arguments from both the AGC and Yang's lawyer Irving Choh on Friday before giving his judgement.

Mr Tan Ken Hwee, AGC chief prosecutor, urged the High Court to set a new benchmark in sentencing and take firm and decisive action because Singapore's rapidly ageing society means that there will be more vulnerable seniors. He cited two recent cases where elderly and vulnerable victims were cheated by people they trusted.

He pointed out that Yang had caused a high level of harm to the victim and that he was highly culpable in the crimes because Madam Chung was vulnerable and had placed an extraordinary amount of trust in Yang who was her caregiver.

"The Singapore public has witnessed, though this case, elder financial abuse at its most egregious, said Mr Tan.

Yang's lawyer, Mr Irving Choh of Optimus Chambers LLC, disagreed.

Mr Choh argued in a written submission that the six-year jail term was "not manifestly inadequate and should be upheld". He said that Principal District Judge Bala Reddy, who sentenced Yang in September, had already considered the aggravating factors of the case and imposed a higher than normal jail sentence for the amount that was misappropriated.

Mr Choh produced in court a table of criminal breach of trust offences and punishments to argue that the jail sentence of more than 10 years sought by the AGC would be "manifestly excessive and crushing".

Yang was also jailed for two years and two months in September last year for a slew of crimes over his immigration status, including falsifying receipts for a sham company in order to stay in Singapore and obtain permanent residency. He will serve a total of 11 years and two months in jail.

His permanent residency was revoked by the Immigration and Checkpoints Authority in November last year, after he was convicted and sentenced by the State Courts.

Yang had met Madam Chung, a retired physiotherapist, in 2008 when he acted as her private tour guide during a China trip. A year later, he moved into her bungalow in Yio Chu Kang and claimed the widow wanted him to be her "grandson".

Madam Chung's husband Dr Chou Sip King, died in 2007 and the couple have no children.

Yang had pleaded guilty to misappropriating $500,000 in February 2010 and $600,000 in January 2012 from Madam Chung. His crimes came to light in September 2014 when he was arrested and charged a month later.

While the criminal trials may have come to an end, Yang faces a High Court law suit brought by Madam Chung's niece Hedy Mok. Madam Mok has sued Yang for manipulating her aunt into handing over control of her assets estimated to be worth $40 million.