The Australian white supremacist suspect in the mosque shootings that's left at least 50 people dead in New Zealand had travelled to the Balkans in the past three years, where he toured historic sites and apparently studied battles between Christians and the Ottoman empire.
Authorities in Bulgaria, Turkey and Croatia have confirmed that Brenton Tarrant, 28, visited their countries in 2016-2018.
Hungarian counterterrorism authorities also suggested that Tarrant had visited but revealed no other information, and local media in Bosnia reported a 2017 trip there.
While the details of Tarrant's travels are sketchy, authorities in those countries said they are investigating his movements and any contacts he might have had with local people.
During his unprecedented, live-streamed shooting spree on Friday in Christchurch, Tarrant exposed his apparent fascination with the religious conflicts in Europe and the Balkans - a volatile region that has been the site of some of Europe's most violent clashes.
Tarrant's soundtrack as he drove to the Christchurch mosque included a nationalist Serb song from the 1992-95 Bosnian war that tore apart Yugoslavia. The song glorifies Serbian fighters and former Bosnian Serb political leader Radovan Karadzic - the man jailed at the United Nations war crimes tribunal in The Hague for genocide and other war crimes against Bosnian Muslims.
Tarrant's rifles contained the names of legendary Serbs and Montenegrins who fought against the 500-year-rule of the Muslim Ottomans in the Balkans, written in the Cyrillic alphabet used by the two Orthodox Christian nations.
In a 74-page manifesto that he posted on social media, Tarrant said he was a white supremacist who was out to avenge attacks in Europe perpetrated by Muslims.
While Serbia and Bosnia have not confirmed that Tarrant had visited, police in neighbouring Croatia issued a statement saying he was in the country in December 2016 and January 2017.
"Until that moment yesterday (in New Zealand), that person was not in the focus of our institutions," Croatian Prime Minister Andrej Plenkovic told reporters according to the official HINA news agency.
In Bosnia, the local Klix.ba news portal reported that Tarrant arrived in that country from Montenegro in early January 2017.
Bulgaria's chief prosecutor, Sotir Tsatsarov, said that Tarrant last year rented a car and toured more than a dozen cities, visiting historic sites from November 9 to November 15. He was mainly interested in the battles between Christians and the Ottoman army, the prosecutor said.
Turkey is also investigating Tarrant's movements during his two reported visits to the country that straddles Europe and Asia and who had three citizens injured in Friday's slaughter.
Serbian President Aleksandar Vucic said the New Zealand shooting is "a terrible crime conducted by a psychopath". He criticised foreign and domestic media for somehow implying that Serbs should be blamed for the crime because of the gunman's "taste for music."