Significant events are frequently followed by discussions about the event's ‘true nature’. Yet, there is only little evidence whether the conspiratorial reasoning of conspiracy believers and sceptics is a priori determined, or if certain characteristics of information are responsible for provoking a polarization. We investigated how depicted causation (direct vs. indirect; Study 1) and intention (strong vs. weak purposeful; Study 2) might invoke a bias in believers and sceptics regarding conspiratorial reasoning about an ongoing event, namely, whether US investigations against FIFA were more or less likely to be seen as a conspiracy against Russia to sabotage the football World Cup in 2018. We revealed that judgments of conspiracy believers and sceptics about the event's ‘true nature’ are not a priori divided—in fact, conspiracy formation is only affected when direct causation or strong purposeful intentions were obvious. Results point to the relevance of conspiratorial predispositions and semantic cues in conspiracy formation. Copyright © 2016 John Wiley & Sons, Ltd.