When an eyewitness suffers an impairment of memory for a perpetrator because the criminal used a weapon during the crime, this impairment is called the weapon focus effect. The literature is split on how this arises: Some implicate the narrowing of attentional cues to the weapon because the arousal of the victim increases, whereas others claim that the weapon is a novel object in most everyday contexts, and novel objects demand more attention than contextually appropriate ones. The current study employed a simulated crime paradigm featuring a normal, novel, or threatening object. Timing of the object's presentation was manipulated such that it was visible before, after, or during the time when the culprit's face was visible. Target‐present and target‐absent line‐ups as well as retrospective questions were administered. Both the novel object and the weapon resulted in increased mistaken identifications in target‐absent line‐ups. Structural equation modeling suggested that object novelty mediated this effect. Copyright © 2014 John Wiley & Sons, Ltd.