Every person offending against any of the provisions of law relating to bribery or corruption shall be a competent witness against another so offending and shall not be excused from giving testimony tending to criminate himself or herself.
RCW 9.18.080
Bribery and corruption: Chapter 9A.68 RCW.
Incriminating testimony not to be used: RCW 10.52.090.
Rights of accused persons: State Constitution Art. 1 s 9.