The blue wall of silence,[1] also blue code[2] and blue shield,[3] are terms used to denote an informal code of silence among police officers in the United States not to report on a colleague's errors, misconduct, or crimes, especially as related to police brutality in the United States.[4] If questioned about an incident of alleged misconduct involving another officer (e.g., during the course of an official inquiry), while following the code, the officer being questioned would perjure themselves by feigning ignorance of another officer's wrongdoing.
^Chin, Gabriel; Wells, Scott (1998). "The "Blue Wall of Silence" and "the Blue Curtain of Secrecy" as Evidence of Bias and Motive to Lie: A New Approach to Police Perjury". University of Pittsburgh Law Review. 59: 233. SSRN1810012.
^Ann Mullen (November 8, 2000). "Breaking the blue code". Metro Times. Archived from the original on June 3, 2020. Retrieved December 29, 2014.