It has been suggested that we lie at least twice a day and that liars betray themselves through a series of verbal and nonverbal behaviours known as leakage cues. In this paper, we have aimed to distinguish between two types of lie (1) “deliberate falsifications” and (2) “feigning knowledge” and determine if they are betrayed in a similar fashion and could be accurately detected. This investigation took part over two experiments. Experiment 1 required participants a take part in a filmed interview in which they responded to a questionnaire and recounted a holiday story. Both of these were carried out twice; once truthfully and once untruthfully. In the cases of untruthful responses we attempted to measure ‘deliberate falsification’ when responding to the questionnaire and ‘feigned knowledge’ when recounting holiday stories. The footage of the filmed interviews was made into a video for experiment 2, in which a separate set of participants viewed the video and were asked to determine the lies from the truths for the questionnaire clips, and to rate a “feeling of another’s knowing”, how certain they believed the people in the clips were about their story. These clips were presented in either an audio- only or visual- only condition. It was found people perform moderately in determining deliberate falsifications with an accuracy rate of 58.13% (t= 3.38, df=23, p<0.05). The condition of the stimuli for feigning knowledge was found to have no bearing on accuracy with non-significant results when the clip was truth/lie (F(1,23)=0.373, p>0.05) or audio/visual (F(1,23) = 0.311, p>0.05). There was a significant interaction between the two types of condition (F(1,23)=6.811, p<0.05). The study has shown that the cues produced when feigning knowledge are more similar to those produced during deliberate falsifications than those for “feeling of knowing” suggesting, the two types of lies aren’t as different as originally believed.