SEOUL (REUTERS) - South Korean prosecutors arrested four people, including a former Goldman Sachs Group Inc employee, suspected of involvement in the manipulation of stock in a small Korean company in 2011, Yonhap News Agency reported on Thursday.

The Southern Branch of Seoul District Prosecutors' Office on arrested the former Goldman Sachs employee for allegedly receiving about 100 million won (S$118,722) and assisting the manipulation of shares in conveyor belt maker Dong Yang P&F by getting other traders to buy shares in the company, Yonhap reported, citing the prosecutor's office.

It did not say when the arrests took place.

The former employee was part of Goldman Sachs' South Korean asset management unit, which announced its shut-down in 2012, the firm's South Korean unit said in a statement.

The statement said that none of the trading under investigation took place at Goldman Sachs, and that the firm had never bought or sold shares in Dong Yang and has been cooperating with prosecutors since last week.

Other media reports citing the prosecutors' office said authorities in the same case had also visited Macquarie Asset Management Korea Co Ltd, which was ING Investment Management Korea until Macquarie Group Ltd bought it in December 2013.

A Macquarie spokesman declined to comment.