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United States: Expert Testimony on “Suicide by Cop” Theory Ruled Admissible

(Aug. 20, 2009) The United States Court of Appeals for the Ninth Circuit has held that in a case alleging excessive police force, a trial court may admit expert testimony that a person shot by police was committing “suicide by cop.”

“Suicide by cop” refers to a method of suicide in which a person purposefully behaves in a manner that compels police to kill him or her. In San Francisco, on May 4, 2004, Cammerin Boyd attempted two armed kidnappings of women within several minutes. Police were alerted, and a high-speed chase ensued in which Boyd shot at police and they shot back. When the chase ended and the car was surrounded by police, Boyd, instead of getting down on the ground as instructed, walked towards the officers and then back to his vehicle, reaching into it, at which point an officer fatally shot him. Boyd's family sued the City of San Francisco, claiming excessive use of force.

At trial, the city proffered a forensic psychiatrist as an expert witness to present testimony that the circumstances indicated Boyd was attempting to commit suicide by cop. The trial court conducted a hearing, outside the presence of the jury, in which the expert was cross examined. The trial court evaluated the proffered testimony under the standards governing scientific expert testimony. It found that the theory was generally accepted within the field of psychiatric forensics and that the testimony otherwise met the standards for admission. Following the trial in which the forensic psychiatrist testified, the jury returned a verdict in favor of the city. Boyd's family appealed, asserting the trial court's decision to admit the suicide by cop expert testimony violated the rules of evidence.

The Ninth Circuit found that Boyd's actions were consistent with an attempt to commit suicide by cop, particularly in light of various aspects of Boyd's personal history that made it more probable that Boyd was attempting to provoke a police shootout rather than trying to surrender. The court found the suicide by cop theory to be an acceptable scientific theory within the field of psychiatric forensics and determined that the trial court did not err in admitting the testimony. (Boyd v. City and County of San Francisco, No. 07-16993 (Aug. 7, 2009), available at