Olympic silver medallist Nam Hyun-hee has been barred from leaving South Korea, police said Tuesday, as a high-profile fraud probe into her ex-fiance drags in the former fencer.

The 42-year-old, who won silver at the 2008 Beijing Olympics, was questioned by Seoul police on Monday over possible involvement in her former fiance's fraud charges.

The case has dominated headlines in South Korea for weeks because of its murky nature and revelations about the pair and their relationship.

Nam's former fiance, Jeon Cheong-jo, was arrested last week on charges of swindling at least 15 people out of 1.9 billion won ($1.45 million).

The 27-year-old Jeon has told local media that the majority of the money was spent on Nam, including buying her a new Bentley and repaying her loans.

A police station in the Songpa district of Seoul told AFP that Nam was subject to a travel ban as part of the ongoing investigation.

"We plan to proceed with the investigation swiftly," police said in a statement to AFP.

The case first came to public attention last month when Nam announced her engagement, giving a magazine interview with her fiance in which they said Jeon was the son of a wealthy family in the casino industry.

However, local media quickly revealed — citing court documents — that Jeon was legally a woman and had been convicted previously of fraud.

Underlining how the case has captivated South Korea, mangled English and Korean phrases used in leaked text messages sent by the fiance to Nam have become top-trending memes online.

Former fencer Nam — who also won bronze at the London 2012 Olympics — has since broken off the engagement, saying that she was deceived and had been unaware of her ex-partner's criminal past.

But a couple who reportedly fell victim to a fraud exceeding 1.1 billion won have lodged a lawsuit against Nam, identifying her as Jeon's alleged accomplice, according to local reports.

The lawsuit prompted the ongoing police probe, reports say.

Since her retirement in 2019, Nam has been operating a fencing club that provides lessons in the upscale district of Gangnam in Seoul.