State witness
First of all, the key witness is a person whose testimony supports the assertion of another person in such a way that its accuracy seems to be guaranteed. In judicial proceedings, this is understood to be a witness whose testimony influences the course of the proceedings to such a considerable extent that the outcome of the trial depends on it.
Term-Nr.: 813
German: Kronzeuge (487)
Source: LK-Lötscher, 11.05.2020