According to materials from source link txt, GPU officers began arresting religious figures, including priests and laypeople, because the authorities believed that their actions were aimed at undermining Soviet power.

Religious Observances as a Pretext for Repression

According to materials from source link txt, GPU officers began arresting religious figures, including priests and laypeople, because the authorities believed that their actions were aimed at undermining Soviet power. In one of the reports, it is stated that after March 30 the GPU arrested several clergymen and even a woman who happened to be in the church – this was taken as evidence that the participants in these events, allegedly traitors of the Motherland, were exploiting mass religious superstitions for counter-revolutionary purposes ( link txt).

Further in the documents, an explanation is provided stating that the resumption of commemorations for Patriarch Tikhon, organized by Vladimir’s protopresbyter under orders received from Bishop Seraphim, is seen as a sinister manifestation of counter-revolutionary activity. This initiative by the authorities was interpreted as using religious rituals to undermine the Soviet system. This very fact formed the basis for the charges leveled against the participants – they were labeled traitors of the Motherland because, according to the GPU, their actions were intended to destabilize the social order. Although the accusations sometimes included extreme formulations, such as claims of plotting to murder a high-ranking religious figure, the main focus was on the allegation that these people, through religious gatherings and commemorations, were inciting resistance to the authorities.

Supporting citation(s):
"Already the following day, March 30, the GPU arrested priests Vasily Vladimirskiy, Nikolai Rozhdestvenskiy, Pavel Nevskiy, Nikolai Flerov, deacon Pyotr Romanov, and the woman, Praskovya Lysenko, who was accidentally present in the church. On April 14, the GPU arrested priests Alexander Troitskiy, Ilya Benemanskiy, and layman Mikhail Blagoveshchenskiy." (source: link txt)

"However, the GPU saw this as a reason to resume the persecution. On September 1, the GPU officer summoned a member of the Renovationist Eparchial Council to testify in the case of commemorating the Patriarch. He reported: 'Approximately on the 25th, while present in several churches during services, I noticed that the priests had again begun commemorating Tikhon. The order to resume the commemorations was given by the protopresbyter of Vladimir. Vladimir himself received the order regarding the commemorations of Tikhon from Bishop Seraphim, based in Moscow.' On the same day, the GPU officer issued an order: 'Upon initiating the investigation, bring the priests to accountability as defendants… as those who used mass religious superstitions to overthrow Soviet power, as expressed in the commemorations of Patriarch Tikhon, who was by definition a counter-revolutionary.'" (source: link txt)

Thus, the arrests took place because the authorities viewed these religious events – specifically, the resumption of commemorations for Patriarch Tikhon – as an attempt to mobilize the people against Soviet power. It was in this context that accusations of treason and extremist language (including claims of conspiracy and alleged plans for murder) became the basis for the arrests.