An investigation into the death of an elementary school teacher that triggered months of teachers’ protests will end without further proceedings, police said Tuesday.

In a briefing Tuesday, Seocho Police Chief Song Won-young told media the investigation into the suicide of a teacher at Seoul’s Seo2 Elementary School had found no evidence of criminal activities.

The 24-year-old teacher died on July 18 in a storage area in the school in Seocho-dong, an affluent neighborhood in southern Seoul. She was in her first year of teaching, and taught pupils in the first grade.

Protests by teachers erupted across South Korea, amid allegations her suicide was caused by bullying by pupils' parents, especially those involved in an incident dubbed the "pencil case" in which one student scratched another.

The police, however, concluded her suicide was brought on by stress from work and personal problems.

The NFS report on the case suspects her psychological difficulties were aggravated by school-related problems, including teaching, mediating conflicts among parents, and administrative tasks.

The police also reviewed documents related to the teacher's colleagues, friends, and parents of her students.

The probe, carried out by a 20-member task force, investigated 68 people, including communications the teacher had with parents, as well as her individual notes and diary, the police said.

Police reviewed records in parents’ mobile phones and testaments from other teachers and students who attended the mediation meeting for the "pencil case" were also reviewed. No indication of verbal abuse was found.

On claims that parents continually called her private phone number, police explained that the calls were to her official business number. The teacher had misunderstood the situation because the calls were also automatically logged on her private phone.

Meanwhile, parents involved in the Pencil Case have accused internet users of defamation. Police have identified 13 commenters so far.

The demonstrations triggered by her death continue across Korea, with 11 held in Seoul.

Seoul Teachers’ Union, a local association of teachers, condemned the police’s decision to close the case, dubbing it a “passive investigation” and called for a reinvestigation, while requiring the education authorities to designate her case as a workplace death, according to local media reports.