Updated

German authorities have arrested a Syrian man suspected of joining the extremist Nusra Front and then the Islamic State group in Syria. They believe he tried to recruit refugees in Greek camps for extremist cells in Europe.

Federal prosecutors said the 31-year-old, identified only as Zoher J. in line with German privacy rules, was arrested Wednesday in Bavaria. They said the arrest was unrelated to an investigation of explosions targeting soccer team Borussia Dortmund.

Prosecutors say the suspect founded a Nusra Front unit in 2011 along with two other men previously arrested in Germany. The unit was later dissolved and the suspect allegedly joined IS, working for its "secret service."

Prosecutors allege that he traveled to Germany in that function in 2015, and traveled back and forth to Greece.