Independent Crime Laboratories: The Problem of Motivational and Cognitive Bias
Read the introduction to this case study and then read part 1. Forensic scientists (who are supposed to remain impartial) can become partisan and see their function as helping the police. Motivation bias is usually conscious and may depend on one's personal situation. You may be interested in reading the rest of the article and noting the Supreme Court's statement in the conclusion.
Click BUS403-2.6.3-IndependentCrimeLaboratoriesTheProblemofMotivationalandCognitiveBias-pdf..pdf link to view the file.