A training workshop utilising recent research in cognitive lie detection was designed and evaluated. A unique future of the training was that a practitioner (retired police detective) instead of scientists (e.g. the training developers) introduced the techniques. To evaluate the training, 27 experienced police detectives each interviewed one mock suspect (a truth teller or liar) before training, and another group of 23 experienced police detectives interviewed one mock suspect (a truth teller or liar) after training. The police detectives were free to interview the mock suspect in any way they felt appropriate, but those who had received training were asked to try to incorporate (some of) the taught techniques in their interviews. The detectives made veracity judgements, and the interviews were transcribed and coded for the amount of detail elicited and the questions asked. Training had a modest effect on the ability to distinguish between truths and lies but resulted in a higher percentage of appropriate questions asked. Trainees did not implement the taught techniques to an equal extent, but when they did, the techniques enhanced the elicitation of information. The training study also revealed challenges, particularly difficulty in implementing the taught techniques into practice and asking the right questions to elicit differences in detail between truth tellers and liars. Copyright © 2015 John Wiley & Sons, Ltd.