The victim, a woman in her 60s, was declared dead at 2 a. The suspect, a 23-year-old male delivery worker who has been identified only by his surname, Choi, drove onto a sidewalk near a subway station in Seongnam, a city southeast of Seoul. Thursday’s attack, which the authorities have said is being treated as an “act of terror,” comes shortly after another stabbing episode last month in Seoul that killed one and injured three