There is no information yet about who did this, but it is noteworthy that the church was just repaired. “The subject peoples … are forbidden to build new churches.” (Reliance of the Traveller, o11.5). Islamic law also forbids Christians to repair existing churches. That this was a jihad attack cannot be ruled out.

“Bosnia: Recently repaired Orthodox church set on fire,” b92.net, June 25, 2018:

Unknown perpetrators have set a Serbian Orthodox church on fire in the town of Visoko, in the Croat-Muslim entity (FBiH) of Bosnia-Herzegovina.

Sarajevo-based website klix.ba is reporting that the incident happened in the night between Saturday and Sunday, and that “a majority of objects” inside the Church of the Nativity of the Theotokos – including icons and holy books – has been destroyed, along with a portion of the roof.

A local website in Visoki said that the main part of the altar has also been “broken.”…

Klix.ba noted in its report that this church was previously repaired over a period of two years, to be consecrated in September 2017.