Jehovah's Witnesses in Russia face a tough choice: be persecuted at home or become refugees abroad.
The EU's top court found that the Jehovah's Witnesses' door-to-door preaching is a form of data collection and requires consent.
Russia considers a wide range of political and religious dissent as "extremist" views.
Russia's crackdown on Jehovah's Witnesses comes as part of a government-backed drive against "foreign" religions.
Several Witnesses have died in prison over the past year, while others have been behind bars since 1994.
International human rights experts argue that Russia's persecution of the Jehovah's Witnesses is in violation of international human rights agreements.
The Kremlin has closed Jehovah's Witnesses prayer halls and banned the group's translation of the Bible as part of a campaign against minority religions.
The raids were conducted by around 150 police officers, who nicknamed their operation "Judgement Day," sources told Newsweek.
The religious group's administrative center in St. Petersburg, Russia, was seized by the government on Thursday.
There have been at least seven raids in the past four months.
The potential investigation follows news of letters and internal documents that show a pattern of sexual abuse by one Jehovah's Witness member, and the lengths the church went to cover up the scandal.
Jehovah's Witnesses have now exhausted the legal options regarding their ban within Russia.
A crackdown on Jehovah's Witnesses in Kazakhstan has followed similar actions against the Christian group in neighboring Russia.
Two Jehovah's Witnesses were recently given a prestigious parenting award, despite the group being regarded as "extremist."
The detention of Dennis Christensen is the first since Russia's Supreme Court upheld a ban on Jehovah's Witnesses nationwide.
Even though an appeal has yet to be heard, an order banning Jehovah's Witnesses in Russia has already had a significant impact.
Satanic Church members are marking their one-year anniversary as an officially recognized religion in Russia while Jehovah's witness branches have been eliminated.
Russia's Catholic Church has joined the chorus of groups condemning the country's ban on Jehovah's Witnesses.
The U.S Commission on International Religious Freedom has designated Russia a "country of particular concern" for the first time.