In recent years, the fight against (violent) extremism has focused more on anticipating the threats that they pose. Therefore, early detection of undemocratic ideas by local professionals has become an important part of the preventive approach in counter terrorism radicalisation. Frontline workers who operate in the arteries of society are encouraged to identify processes toward violent behaviour at an early stage. To date, however, little is known about how these professionals take on this screening task at their own discretion. The analysis of 55 interviews with youth workers, municipality civil servants, and community police officers, show that they tended to be insufficiently equipped in general to detect radicalisation towards (violent) extremism at the local level in the Netherlands. Firstly, this is due to varying contents and qualities of training courses which are not suited to building up solid expertise. Secondly, and most importantly, the recognising of deviant behaviour is presumably carried out with a one-sided focus on personal norms and values rather than structured judgements about pathways towards risky behaviour. Various value systems seem to influence the norm for early detection, which means that there is, in practice, a lack of clear indicators.