By January 1914, a renewed clampdown on the "Old Ruthenian" movement left Bogatyrets without his parish.
In August–September, just as World War I broke out, areas of Bukovina fell to a Russian occupation.
Before the Austrian evacuation, Czernowitz's police chief, Konstantin Tarangul von Valea Utsei, ordered Bogatyrets' arrest.
He was transferred to an internment camp at Sankt Marien, in Upper Austria, then to the prison-garrison of Vienna.
Stefanida was also detained some days after her husband, and deported to Talerhof.
Bogatyrets was eventually tried, alongside Hilarion Tsurkanovich (Curkanovič) and 20 other defendants, from September 14, 1916, to February 17, 1917.
As he himself later recalled, the indictment was 360 pages in length, all of them "fictitious".
He was one of 17 sentenced to death by hanging.
An appeal was filed, although, allegedly, Bogatyrets had refused to ask for clemency.
Eventually, under the terms of a general amnesty granted by Emperor Charles, all the defendants were spared punishment, and Bogatyrets was assigned domicile in Graz.

Eventually, in September 1917, Bogatyrets was allowed back in Verenchanka to resume work as a parson.
By November 1918, the Austrian monarchy had collapsed.
Bukovina, following skirmishes between the Ukrainian Galician and Romanian armies, was occupied by the latter.
As the Romanian provisional military administration negotiated a transition to civilian rule, he reemerged as his community's political organizer; the core Ukrainian leadership, including Pihuliak, Stepan Smal-Stotskyi, and Volodymyr Zalozetsky-Sas, had left the region in protest, confident that the Paris Peace Conference would rule in favor of the Ukrainian People's Republic.

For a while, Bogatyrets cooperated with the conservative Romanian Iancu Flondor of the General Congress, who supported regional autonomy for Bukovina within Greater Romania.
In June, Romanian General Nicolae Petala heard complaints from a trans-ethnic coalition, expressing support for the autonomy of Bukovina: Bogatyrets was a representative of all Ukrainian groups; others to speak were the Romanians Flondor and George Grigorovici, Germans Albert Kohlruss and Rudolf Gaidosch, and Jews Mayer Ebner and Iacob Pistiner.
As the Ukrainian People's Republic lost ground to the rival Ukrainian Soviet Socialist Republic, Bogatyrets signed a plea addressed to the Allies.
Presented there by the Czechoslovak delegation, it argued for the creation of a new Ukrainian state—comprising Bukovina, Eastern Galicia, Carpathian Ruthenia, Bessarabia, and Maramureș/Maramorosh.
Bogatyrets had included a historical overview, which asserted that Bukovina was ancestrally Ruthenian, and a map, which suggested that the Ukrainians and Rusyns were a majority of the population in Bukovina.
By January 1914, a renewed clampdown on the "Old Ruthenian" movement left Bogatyrets without his parish. In August–September, just as World War I broke out, areas of Bukovina fell to a Russian occupation. Before the Austrian evacuation, Czernowitz's police chief, Konstantin Tarangul von Valea Utsei, ordered Bogatyrets' arrest. He was transferred to an internment camp at Sankt Marien, in Upper Austria, then to the prison-garrison of Vienna. Stefanida was also detained some days after her husband, and deported to Talerhof. Bogatyrets was eventually tried, alongside Hilarion Tsurkanovich (Curkanovič) and 20 other defendants, from September 14, 1916, to February 17, 1917. As he himself later recalled, the indictment was 360 pages in length, all of them "fictitious". He was one of 17 sentenced to death by hanging. An appeal was filed, although, allegedly, Bogatyrets had refused to ask for clemency. Eventually, under the terms of a general amnesty granted by Emperor Charles, all the defendants were spared punishment, and Bogatyrets was assigned domicile in Graz.
Eventually, in September 1917, Bogatyrets was allowed back in Verenchanka to resume work as a parson. By November 1918, the Austrian monarchy had collapsed. Bukovina, following skirmishes between the Ukrainian Galician and Romanian armies, was occupied by the latter. As the Romanian provisional military administration negotiated a transition to civilian rule, he reemerged as his community's political organizer; the core Ukrainian leadership, including Pihuliak, Stepan Smal-Stotskyi, and Volodymyr Zalozetsky-Sas, had left the region in protest, confident that the Paris Peace Conference would rule in favor of the Ukrainian People's Republic.
For a while, Bogatyrets cooperated with the conservative Romanian Iancu Flondor of the General Congress, who supported regional autonomy for Bukovina within Greater Romania. In June, Romanian General Nicolae Petala heard complaints from a trans-ethnic coalition, expressing support for the autonomy of Bukovina: Bogatyrets was a representative of all Ukrainian groups; others to speak were the Romanians Flondor and George Grigorovici, Germans Albert Kohlruss and Rudolf Gaidosch, and Jews Mayer Ebner and Iacob Pistiner. As the Ukrainian People's Republic lost ground to the rival Ukrainian Soviet Socialist Republic, Bogatyrets signed a plea addressed to the Allies. Presented there by the Czechoslovak delegation, it argued for the creation of a new Ukrainian state—comprising Bukovina, Eastern Galicia, Carpathian Ruthenia, Bessarabia, and Maramureș/Maramorosh. Bogatyrets had included a historical overview, which asserted that Bukovina was ancestrally Ruthenian, and a map, which suggested that the Ukrainians and Rusyns were a majority of the population in Bukovina.
Kassian Bogatyrets