The six South Koreans who were recently returned home from North Korea were found to have entered the communist country illegally via China, public safety authorities here said Sunday.

Last Friday, North Korea handed over the six men along with the body of a South Korean woman at the neutral border village of Panmunjom.

The men were immediately taken into the custody of South Korean authorities for questioning on how they entered the North and details of their stay there.

According to the authorities, all six men said they had entered North Korea illegally between 2009 and 2012 by jumping off a Chinese cruise ship in the rivers along the North Korea-China border or by walking across the rivers when they were frozen over.

The six were identified as a 44-year-old surnamed Kim, a 27-year-old surnamed Song, a 67-year-old surnamed Yun, a 65-year-old surnamed Lee, a 43-year-old surnamed Chung and a 56-year-old surnamed Hwang.

The authorities said some of the men had posted pro-North Korea writings on the Internet under false names and had fallen under the

delusion that they would be treated well by the North Korean government when the communist country's official media introduced them by their pseudonyms.

Some of the men were found to have worked as day laborers due to family troubles, business failures and other hardships when they decided to flee to the North, thinking that their lives would improve there, the authorities said.

One man told the authorities that he believed he would be able to restore his poor health and improve his life in general if he moved to the North.

The men testified that they had been held and questioned in various detention centers across North Korea for up to 45 months before being rounded up at one center ahead of their repatriation, according to the authorities.

The men expressed their disappointment and sense of betrayal at the way they were treated in the North, with some saying that they were not treated for their health problems or allowed to leave their rooms at the detention centers, the authorities said.

One man claimed that he weighed less than 40 kilograms because he had not been able to eat properly without any teeth.

Lee, one of the six men and the husband of the South Korean woman whose body was sent back, claimed he and his wife had planned on committing suicide together, but he failed to kill himself after strangling his wife to death, the authorities said.

The authorities said they have sought arrest warrants for the six and will question them further once the warrants are issued.

Under South Korean law, all six men could be charged with violating the National Security Law, while Lee could also be charged with murder, the authorities said. (YONHAP)