In October 2006, a New Hampshire police officer named Michael Briggs was shot to death in an alley. His accused killer, Michael Addison, has been charged with capital murder. It is the state's first death-penalty case in more than 30 years, and it is racially fraught: Addison is African-American, and Briggs was white. New Hampshire has a long list of procedures that are intended to minimize racial bias in capital cases. However, Addison's lawyers say that these safeguards are not strong enough to purge bias from the death-penalty apparatus. To prove that racism can operate powerfully at an unconscious level, Addison's lawyers brought forward a witness--Mahzarin R. Banaji, a psychologist who has published many papers based on the implicit-association test, a computer-based assessment that measures in milliseconds how quickly a person associates positive or negative words with stigmatized groups. This article examines the debate concerning the use of implicit-bias test for legal purposes.