The Murder Friday of September 29, 1714 was a massacre in the island of Hailuoto (Karlö), Finland, then part of the Kingdom of Sweden. It was the deadliest single act of Russian terrorism against the civilian population during the Great Wrath, which was part of the Great Northern War (1713–1721). On that Friday, about 200 Cossacks killed almost all the civilians who had fled to the island from the Russian troops. The civilians had fled to the island mainly from the towns of Nykarleby, Jakobstad, Kokkola and Raahe, as well as from coastal areas. Their intention was to escape the Russians to Sweden. According to tradition, there were about 800 victims; also, according to same tradition, the bells of Hailuoto Church were drowned in Lake Kirkonjärvi, where they were never found again.