Park Won-soon was reported missing by his daughter at around 5 p.m. Thursday (4 a.m.ET), according to a police officer familiar with the matter.
The longtime 64-year-old civic activist, who has been mayor of Seoul since 2011, is considered a likely hope for the Liberals in the 2022 presidential election.
When Park was elected in an overwhelming victory against the ruling party almost a decade ago - without political connections or experience - it sparked a public frenzy. His unexpected rise to the country's second most powerful position was seen as a sign that the South Koreans were tired of traditional politics.
The former human rights lawyer, who ran independently but forged an alliance with opposition parties, championed city protection projects and became a symbol of reform.
He was re-elected mayor in 2014 and again in 2018.
It's a developing story, more to come ...
