The Dutch government should acknowledge in public the fact that it’s very difficult to pick out jihadists from asylum seekers, criminologists have argued.

Writing in daily newspaper NRC, university of Amsterdam researchers Joris van Wijk and Maarten Bolhuis say the public’s expectations that the government is able to screen would-be terrorists from asylum seekers are unrealistic.

Following the release of a report which said screening of migrants is inadequate, and the terror attack last month in Berlin in which a Tunisian man ploughed a truck into people at a Christmas market, the government sought to calm public fears.

“We’ll pick out the terrorists at a later stage”, the then justice minister Ard van der Steur told the Telegraaf in response to the inspection report, a comment that van Wijk and Bolhuis say sounded “reassuring” but was not necessarily realistic.

The criminologists report that staff working at the Netherlands’s Immigration and Naturalisation Service (IND), and its Central Agency for the Reception of Asylum Seekers (COA) say it’s unrealistic to expect that would-be terrorists can be picked out among newcomers.

The IND issues guidelines detailing possible indicators of Islamic extremism which includes certain behaviours (such as refusing to shake hands with women), certain language, and other outward mannerisms.

However, in the report, the list was criticised by security experts from the Netherlands’s security and counter-terrorism agency, and van Wijk and Bolhuis note: “There is ample scientific literature to back up the contention that establishing a reliable method to spot jihadists is very difficult indeed.”

The report concluded that while bodies involved in the asylum chain are doing their best, it’s very hard to detect Islamic extremists. It also noted there are other factors which make attempts to do so more complex, such as that jihadist social media accounts are explicit in telling Islamists to keep a low profile and act normally.

Van der Steur’s assertion that terrorists can be “picked out” was misleading and “suggests, incorrectly, that the IND or COA are actually able to identify jihadists who enter the country”, Van Wijk and Bolhuis say.

The criminologists call on ministers to admit that “no one really knows how to” separate jihadists from asylum seekers.

“You may not sleep as soundly as Van der Steur would like you to, but the truth would be better served” the piece, which was published in NRC, concludes.