A primary school teacher wrote on 3 July that she “wanted to let go” of the craziness of her work.

The 23-year-old’s body was found in her classroom store cupboard two weeks later. Her suicide was self-inflicted.

Primary school teachers across South Korea have been infuriated by this tragedy. A strike by tens of thousands of them took place on Monday to demand better workplace protections. Overbearing parents often harass them at all hours of the day and on weekends, complaining incessantly and unfairly.

As Park Du-yong straightens out Min-so’s small, empty apartment, now home to just her goldfish, her cousin struggles not to cry. An unmade bed sits beside a pile of drawings from her first-grade students, telling her how much they love her. A stack of library books on coping with depression can be found underneath.

Having followed her mother into teaching, Park says his cousin had been teaching for little over a year. He says she loved the kids.

Park assumed the role of detective after his cousin died, which police quickly attributed to a recent breakup. Hundreds of diary entries, work logs, and text messages were found.

In the months leading up to her suicide, Min-so had been bombarded by complaints from parents. Her pupils had recently slashed another child’s head with a pencil, which led to heated late-night phone calls and messages with the parents.