The immigration authorities are looking into the permanent residency (PR) of Chinese national Yang Yin after questions were raised about how he had obtained it.
Mr Yang, a former tour guide, first came to Singapore to work in 2009 on an Employment Pass.
He was hired by Young Music and Dance Studio, a firm he set up with Madam Chung Khin Chun in March 2009.
The 40-year-old has been accused of taking advantage of Madam Chung, an elderly widow, to get access to her assets, which include a $30 million bungalow in Gerald Crescent.
It is unclear when Mr Yang became a permanent resident, but it is believed to be after 2011.
The Immigration and Checkpoints Authority (ICA) declined to give details of his PR, citing confidentiality.
But a spokesman told The Straits Times yesterday: "The ICA is aware of media reports on the case and is looking into the matter."
The spokesman said PR applications are decided by factors including qualifications, income and length of stay in Singapore.
But he warned: "Individuals who provide false information in their application for immigration facilities will be dealt with firmly under the law.
"In addition, they will have their immigration facilities cancelled or revoked."
Those convicted of offences also risk losing their PR, the spokesman added.
Besides the ICA probe, Mr Yang also faces a police investigation.
The police confirmed that a report has been made against Mr Yang by the Singapore Chinese Chamber of Commerce and Industry for falsely claiming to be the association's director.
Meanwhile, Mr Yang made his first public appearance yesterday afternoon at the Gerald Crescent bungalow.
The 1.7m-tall man turned up in a brown leather jacket and blue jeans with his lawyer to retrieve personal belongings including a bicycle, luggage and a pushchair.
Mr Yang was later spotted in a Housing Board flat in Toa Payoh. He declined to speak to reporters.
A woman in her 50s, believed to be the flat owner, said Mr Yang and his family had been staying with her since last week.
"I've known him for a very long time... since he was in Singapore in 2009," she said in Mandarin, before shutting the door.
When The Straits Times returned to the flat again last night, the same woman said Mr Yang is no longer there.
Mr Yang is believed to have filed an affidavit in court yesterday.
He had previously told reporters he would make a public statement after he filed his side of the story in court papers but he remained uncontactable by phone or through his lawyer yesterday.