Prosecutors in Germany are investigating the activities of a 35-year-old Syrian doctorate student they suspect of being involved in a propaganda video for the Islamic State group.
Prosecutors in Frankfurt also suspect the unnamed man of posting a symbol resembling the IS flag, forbidden in Germany, on his personal page on a social media site.
Police arrested the man Tuesday in the southern city of Darmstadt and also seized a mobile phone and media storage devices from his apartment and office, the prosecutors said.
In a nine-minute video in Arabic posted on the Internet January 7, the suspect is believed to have explained his reasons for supporting IS, the prosecutors said in a statement.
Cases of individuals posting such videos are relatively unusual in Germany, even though prosecutors are investigating dozens of suspected jihadists returning from Syria for being members of IS, a banned organization in Germany.
Authorities are worried about hundreds of people traveling abroad to join militant Islamist groups and some of them returning home, possibly with the aim of plotting attacks.
Germany last year joined an international military campaign against IS insurgents in Syria.
