On Wednesday, Serbia’s capital Belgrade was shocked by a rare shooting in one of the city’s elementary schools. The shooter, aged just thirteen, killed eight of his peers and a security guard before calling the police to report himself.

A day later, apparent copycat crimes began in five other schools: four in Belgrade and one in Bihać, in neighboring Bosnia, where children either drew up kill lists, made threats with toy guns, or assaulted their teachers and peers with knives. Then, on Friday, a second shooting spree occurred, this time to the south of the capital, killing another eight and wounding fourteen.

In both cases, some survivors are still in critical condition and it’s not yet clear if the death toll will rise. In total, the police intervened in twenty-five alleged cases of copycat crimes in Serbia alone. Two further threats were reported in Trbovlje, Slovenia, and two others in Skopje, North Macedonia — confirming fears that the crime will spread across the Western Balkans.