The suicide of a 15-year-old teenage boy has rattled South Korea and has highlighted increasing school violence that has long been in the shadows.

Choi, identified only by his surname, jumped out of his apartment home in the southeastern city of Gyeongsan early this month after being bullied for almost two years.

Choi left behind a suicide note in which he named five students who he said had bullied him physically and verbally since 2011, reports Time.

He also criticized the government-mandated CCTV cameras in schools, which are aimed at curbing bullying: “You’ll never be able to spot school violence the way it is now. There are blind spots in classrooms and restrooms were no closed-circuit cameras are installed. That is where most school violence happens,” Choi wrote, according to Wall Street Journal.

The government announced tougher measures, including increasing security personnel and installing more and higher-resolution closed-circuit cameras, The Korea Herald reports.

But the plans were met with criticism for falling short of curbing school violence. A local government official said schools should focus on preventive measures, such as alleviating pressure on students, rather than surveillance cameras to prevent bullying.

Choi’s death was the second youth suicide in South Korea this month. Government statistics show that suicide is the leading cause of death among 10- to 19-year-olds in South Korea.

Korea’s youth suicide rate jumped nearly 50% from 6.4 to 9.4 per 100,000 people in the past 10 years, according to data from Organisation for Economic Cooperation and Development.

South Korea’s Education Ministry has vowed to address the issue with a nation-wide fact-finding survey on school violence to help determine future anti-bullying policy direction.