(Getty Images Bank) 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 the teacher's chair and fled the scene.The school reported the incidents to police, who reviewed CCTV footage from the corridor outside the classroom and identified the student. He was apprehended on June 8 on suspicion of property damage and trespassing.During police questioning, the student reportedly said he did not know the teacher and denied any sexual motive, claiming he had entered the classroom while looking for a restroom.The teachers' union called for a thorough investigation, saying the teacher has been unable to return to the classroom due to severe emotional distress caused by the repeated incidents.Police said they are investigating whether the acts were sexually motivated and directed at a specific individual, and are considering seeking search warrants for the student's mobile phone, computer and other digital devices.