SINGAPORE - The former China tour guide embroiled in a legal tussle over a wealthy widow's assets is now being investigated by the Ministry of Manpower (MOM).

In response to media queries, MOM said on Thursday that it is carrying out investigations against Mr Yang Yin but declined to provide further details.

The MOM investigation comes on the back of ongoing investigations by the Commercial Affairs Department and the Immigration and Checkpoints Authority.

This is the latest twist in a legal spat involving Mr Yang, 40, and 87-year-old widow Madam Chung Khin Chun over control of her assets, worth an estimated $40 million.

They had met in 2008 when Mr Yang acted as her private tour guide on a holiday in Beijing. A year later, in 2009, Mr Yang came to Singapore on an Employment Pass and moved in to live with the widow. In 2012, he was granted a Lasting Power of Attorney, giving him full control over all the widow's assets.