Following the arrest of a 16-year-old Syrian refugee in Cologne on Tuesday, investigators have found that the crucial piece of evidence leading to the special counterterrorism operation came from a member of the Turkish-German Islamic Association (DITIB). Founded in 1984, the group has around 900 mosque congregations across Germany and represents some 70 percent of the country's Muslims.

DITIB has long been an important point of contact for German authorities. Dr. Marwan Abou-Taam, an expert in international terrorism, domestic safety and Salafism, told DW that it's this bond of trust, which has developed over many years between German authorities and Islamic associations, that can be useful in cases such as that of the Syrian refugee in Cologne.

The teenager was taken into custody on suspicion of links to the self-styled "Islamic State" (IS) group. Authorities described him as a "serious threat who had been planning a bomb attack.

Tip-offs from congregations, however, remain few and far between. "The radical scene is rarely endorsed in congregations which are actually in contact with the police," Abou-Taam said. "We have two structures in Germany of 'legal Islam' and the Salafists - and of course with the Salafists, there's no bond of trust with the police," he added.

The appearance of an unusual character at a congregation would also be quickly noticed, Abou-Taam told DW.

"A congregation is first and foremost an association which has members who are known to each other. But at prayer times, the mosques stand open and anyone who wants to come and pray can enter the building. So the imam can't always be sure who's praying behind him," he said.

"But when a congregation notices that particular people with certain beliefs repeatedly turn up, then they have a vested interest to inform the police," Abou-Taam added.

Terminated cooperation

Despite the tip-off from a DITIB member in Cologne, communication and trust between the state and the association has broken down in recent months.

Most recently, North Rhine-Westphalia's (NRW) interior ministry ended its cooperation with DITIB on the interior ministry-led prevention program "Wegweiser" (Sign posts). The project, which is still running across NRW, aims to protect young people from falling into Salafism.

The partnership was terminated earlier in September after a publication supported by Diyanet, Turkey's Presidency for Religious Affairs, released a children's comic glorifying martyrdom.

As part of its mission, DITIB plays host to imams sent to Germany by Diyanet for five-year periods, during which time their wages are paid by the Turkish state.

Due to DITIB's close connections to Diyanet, NRW's interior ministry called on the association to respond to the publication with a statement. Having failed to do so, NRW severed ties with DITIB.

A spokesman for NRW's interior ministry, Oliver Moritz, said the association's stance didn't comply with that of the prevention program. "We have to distance ourselves from a responsible body that supports martyrdom," he told DW.

'Unreasonable and wrong'

Coordinator of DITIB's state association Murat Kayman argued, however, that the arrest of the 16-year-old suspect shows how "unreasonable and wrong" the interior ministry's decision was to terminate the partnership.

"The attentive conduct of the DITIB congregation in Cologne is a clear example of the association's unequivocal stance on supposedly religiously-legitimated violence, as well as the radicalization of young people," Kayman told DW.

"We will continue to so everything we can to prevent extremism, along with all our DITIB mosques," Kayman said, adding that the decision was politically-fueled, due to Germany's unsteady relations with Turkey over President Recep Tayyip Erdogan's growing repression.

Religious counter narrative

Despite ending the partnership with DITIB, NRW's interior ministry continues to work with a wide group of institutions across the state to try and prevent radicalization, including schools, job centers and family support groups.

Taam told DW, however, that religious congregations - particularly theologians - bear the brunt of responsibility in preventing radicalization.

"lslamist extremists use the foundations of religion to radicalize," Taam said. "If violence is rationalized with religion, then the religion can only fight back if it develops a counter narrative which comes from the congregations."

"This means that it's more believable if an Imam says, 'No, what you're learning isn't Islam,' than when a social worker says it," Taam told DW.

But despite the efforts of Muslim communities and German authorities to try and prevent radicalization, Dr. Stephan Bundschuh, a professor in social sciences at the University of Koblenz, warned that the long-term solution lies somewhat further away from home.

"As long as the destabilized situation in Middle East continues," Bundschuh told DW, "IS will continue to be present."

"They represent that something new after everything else has been destroyed."