People v. Collins

68 Cal.2d 319, 438 P.2d 33, 66 Cal.Rptr. 497 (1968)

Facts

Mr. and Mrs. Collins (D) fit the description that an eyewitness gave of a purse snatcher. The eyewitness described viewing a blond haired white girl with a ponytail and a bearded black male in a yellow car. The prosecutor called a mathematics as a witness to establish the probability that the crime was committed by the accused couple. The expert explained the use of the product rule to determine the probability of a joint occurrence from a number of mutually independent variables. The prosecutor then had the witness assume certain probability factors for the various characteristics which the prosecutor said the guilty couple shared. The professor gave the chance of any couple having the same characteristics as one in 12 million. The prosecutor claimed that this data meant that there was only one chance in 12 million that D were innocent. D were convicted of second-degree robbery, etc.).