corroboration rule

The general rule that an accused may not be convicted on his own uncorroborated confession... Its purpose is to prevent 'errors in convictions based upon untrue confessions alone'; its foundation lies in a long history of judicial experience with confessions and in the realization that sound law enforcement requires police investigations which extend beyond the words of the accused.

Defined by the Supreme Court in - Smith v. United States, 348 U.S. 147 (1954).