German federal prosecutors on Thursday said they had indicted four men on suspicion of supporting Islamist extremist group Jabhat al-Nusra.
One of the men is also accused of joining the group and traveling to Syria to fight with the breakaway offshoot of al-Qaida.
What exactly are the men accused of?
The German citizen Marius A. allegedly went to Syria in October 2013 and joined al-Nusra. He is understood to have remained a member until March 2014 and took part in fighting at least once.
Prosecutors said he also received funds from the group while he was in Turkey.
Marius A. was detained last September in Senegal. He was extradited to Germany in May and remains in custody.
Three other German nationals, with dual or triple citizenship, were also indicted.
They were German-American citizen Maher M., German-Algerian citizen Mohamed S. and the German, Spanish and Moroccan citizen Avid E.G.M.
They are accused of raising money for Nusra at Marius A.'s request and transferring the cash to him in late 2013 or early 2014.
What is Jabhat al-Nusra?
The group, also known as the al-Nusra Front or Nusra, has also been described as al-Qaeda in Syria or al-Qaeda in the Levant.
Rather than focusing on global jihad, its objective was the "near enemy" of the Syrian regime.
Formed in 2012, it was primarily composed of Syrian jihadis who wanted to overthrow President Bashar al-Assad and create an Islamic emirate under Shariah law.
In 2012, the Washington Post described al-Nusra as "the most aggressive and successful" of the rebel forces.
Numerous foreign fighters joined the group, to eventually make up about 30% of its members.
The group was fractured in 2013 by the formation of the "Islamic State," with some members swearing allegiance to that Islamist group and others refusing.
For a time, al-Nusra was the official Syrian branch of al-Qaida, before joining with other Islamist groups to eventually become Hayat Tahrir al-Sham. That group denies being part of al-Qaida.
rc/sms (AFP, AP, dpa)