The rally in front of state prosecutors' offices in Seoul came days after huge crowds poured onto a major boulevard near the city's presidential office demanding the ouster of the minister, Cho Kuk, a close confidant of President Moon Jae-in.
They believe prosecutors are pushing an aggressive probe to rattle Cho, who has been considered a future presidential hopeful for the liberals, because his reform plans include curbing the powers of state prosecutors. Cha Seon-ah, a student from Seoul, said prosecutors were investigating despite a paucity of evidence.
Earlier on Saturday, prosecutors for the second time this week summoned Cho's wife, Chung Kyung-shim, who they indicted last month on suspicions of manipulating an award issued to her daughter from a university where she works as a professor. In South Korea, prosecutors have exclusive authority to indict and seek warrants for criminal suspects and exercise control over police investigative activities. They can also directly initiate criminal investigations even when there's no complaint.