Brigitta Diaz, born in England to Nicolette Martin, is a Californian criminologist who graduated in 1988 in Los Angeles. From her very first unofficial case, Brigitta demonstrated sharpness and intelligence, qualities that allowed her to solve the murder of her professor, Mr. Jefferson, and the Spencer twins, during which she met and became friends with investigator Alfred Derek.

​

She often collaborates with Douglas Polanski, her former college classmate.