In a method for verifying statements made during a call, while the call is in progress, data of a portion of the call is received from a telecommunication device used in the call, at a system over a data network. The portion is related to a statement made during the call. A textual content of the data is subjected to NLP to locate a part of the statement that is asserted as true. The part is extracted from the data. Information is obtained from a data source to determine whether the part of the statement is validated by the information. When the part is invalidated, the part is indicated as false in a result. The result is transmitted to the telecommunication device, while the call is in progress at the telecommunication device, the result. The transmitting causes a change to occur in the call at the telecommunication device.