For 60 years, the study of human lie detection has explicitly asked people, “Is that person lying or telling the truth?” in an attempt to quantify whether and to what extent people can accurately determine credibility. The result of these efforts is the dismal conclusion that people are poor lie detectors. In a meta-analysis, Bond and DePaulo (2006) reported an average accuracy of 54%. Our research explores novel reactions to observing liars, versus truth-tellers. Findings indicate that observers experience increased physiological threat and generalized arousal in response to observing high-stakes emotional lies, versus truths. Further, observers experience less sympathy, are less likely to help, and comfort deceptive murderers versus genuinely-distressed relatives, all pleading for the return of their missing loved one. Observers’ reactions are mediated by emotional facial expressions suggesting that, although behavioral cues to deception are generally weak and unreliable, they do impact observer reactions to deception.