AT least nine people have been killed after a teenage boy opened fire at a primary school. The 14-year-old suspect shot his teacher first before targeting others in Belgrade, Serbia. AFPThe suspect was arrested by cops at the scene[/caption] Eight pupils and a security guard have been killed. One teacher was also injured and is receiving emergency treatment, Tanjug reported. The suspect was arrested and taken away by cops. THIS IS A DEVELOPING STORY… The Sun is your go to destination for the best celebrity news, football news, real-life stories, jaw-dropping pictures and must-see video. Download our fantastic, new and improved free App for the best ever Sun Online experience. For iPhone click here, for Android click here. Like us on Facebook at www.facebook.com/TheSun and follow us from our main Twitter account at @TheSun.