A high school student on Jeju Island is being investigated for allegedly entering an elementary school teacher's classroom on multiple occasions and leaving behind semen and urine, police said Tuesday. According to Seogwipo Police Station and the Jeju Teachers' Union, the student allegedly sneaked into an elementary school near his high school in April and left semen in a teacher's personal tumbler kept in a classroom. On June 4, the student came back to the same classroom, where he urinated on