The man is accused of strangling his elderly parents, his wife, and their teenage and twenty-something daughters while they were asleep in their flat in Yongin, a city about 40km (25 miles) southeast of Seoul, on Monday evening.
Police investigations revealed that he had drugged them with sleeping pills before committing the crime, the ChosunBiz online news outlet reported.
The suspect left a note at the scene stating “I will kill everyone, and I will die too”, before fleeing nearly 280km to the southwestern city of Gwangju early Tuesday morning.
Authorities found him unconscious in a flat and arrested him later that same morning. He was suspected to have taken sleeping pills, but was not in a critical condition.
The accused told police during questioning that he was overwhelmed with money problems after being sued by contractors and buyers involved in a real estate development project, according to The Korea Times newspaper.
