Authorities in Estonia captured the leader of a far-right terrorist group called the "Feuerkrieg Division" (FDK), or ''fire war division,'' an online group with members that spread across several countries, Der Spiegel reported on Thursday.

Investigators found the group was headed by a 13-year-old, the German magazinesaid, citing Estonian newspaper Eesti Ekspress. The young man operated online under the name "Commander" and was responsible for the recruitment and admission of new members.

He also shared bomb-making instructions, spoke about planning an attack on London and suggested organizing military training camps in February, to commemorate the "100th birthday" of Adolf Hitler's former political party NSDAP.

Due to the suspect's age, he cannot be prosecuted in Estonia, Der Spiegel reported. Instead, authorities will have to seek other legal measures to protect him from himself and others.

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Members in Germany

Reports suggest FDK operated almost entirely online and idolized right-wing terrorists as "saints," calling on members to follow their example.

As recently as October, the group wrote a series of tenets such as "we are not afraid to die and we kill anyone who gets in our way." FDK announced its dissolution on February 8, though authorities found internal chats indicating they would continue under a new name.

The group was reportedly active worldwide and had, until recently, some 70 members in 15 countries, including Germany.

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Online radicalization

Der Spiegel reported that the German branch consisted of six members, going by internal chat names of "Heydrich", "Teuton", "Dekkit", "Napola88", "Wolfskampf" and "Jus-ad-bellum."

"Heydrich" was said to be the head of the German organization and he was arrested in Bavaria in February of this year. Investigators found photos of the 22-year-old man posing with a mask on, a self-made rifle and an edition of Adolf Hitler's "Mein Kampf."

The members of FKD are the latest group of suspected right-wing terrorists allegedly radicalized online that security authorities have long overlooked.

According to the magazine, "Heydrich" had no criminal background and no connection to the regional neo-Nazi scene before his activities with the FKD. Instead, he reportedly underwent self-radicalization on the internet, through right-wing chat groups.

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