A South Korean executive is free and back home after more than four months of isolated captivity in North Korea.  His release follows a four-day mission by the corporate chairwoman who employs him, and whose company has invested massively into the North's impoverished economy. 

South Korean executive Yu Seong-jin crossed the heavily armed inter-Korean border, making contact with fellow South Korean citizens for the first time in more than four months.

In a brief statement, Yu said he was happy to be back, and offered thanks to the South Korean government, his employer, and the South Korean people.

A brief media frenzy ensued as reporters tried to question Yu, who has been held incommunicado by the North since late March.  That is when Pyongyang alleged he criticized the North's political system while working in an inter-Korean factory zone in the North Korean city of Kaesong.

Yu was working for Hyundai Asan, a South Korean corporation that has poured hundreds of millions of dollars into the Kaesong zone, and into an inter-Korean resort zone at the North's Kumgang mountain.  Both projects have been celebrated in the past as breakthroughs in cooperation between the two Koreas, which remain technically at war.

Yu Seong-jin's release came after Hyundai Asan Chairwoman Hyun Jung-eun spent four days in Pyongyang, apparently negotiating his fate. The precise agenda during her visit remains unclear.  South Korean Unification Ministry Spokesman Chun Hae-sung says no payoffs were made.

He says South Korea has not given anything to the North in return for Yu's release.

Public attention to Yu's case spiked here in South Korea after last week's swift visit to the North Korean capital by former U.S. President Bill Clinton.

Mr. Clinton arrived in Pyongyang last Tuesday, and by the next morning was boarding a plane with U.S. journalists Laura Ling and Euna Lee, whom North Korean leader Kim Jong Il personally pardoned from a long labor sentence.  They had been convicted of illegally entering the country in March at the Chinese border.

Kim Yong-hyun, a North Korean Studies professor at Seoul's Dongkuk University, says Pyongyang had its reasons for making Chairwoman Hyun's visit longer.

He says North Korea was trying to make the South as anxious as possible in order to maximize political leverage.  In addition, Kim Jong Il was scheduled to be outside of Pyongyang early in the week giving on-the-spot guidance, and was unable to deal with Hyun until later.  

South Korea is still working for the release of four crew members of a fishing boat that crossed into North Korean waters last month.