The Guilty Knowledge Test (GKT; Lykken, 1959) assesses whether suspects conceal information about a crime ("guilty knowledge"). Previous studies have demonstrated larger physiological reactions to guilty knowledge compared to unknown information. In three experiments, we investigated whether guilty knowledge also demands attention. During an alleged polygraph examination, participants were presented with to-be-detected pictures ("guilty knowledge"), nonsignificant, familiar pictures ("mere knowledge"), and previously unseen pictures ("neutral information") for 250 ms in a modified dot probe task. In all three experiments, probe responses were slower on guilty knowledge trials as compared to the neutral trials. Results are discussed in terms of an information-processing view on orienting to guilty knowledge.