Familial searching, which is done in Britain, Australia and New Zealand, has a 10% to 14% success rate, according to countries that use the technique. California's rate so far is about 11%.
Harris, California's first black attorney general, said the disproportionate number of DNA profiles from racial minorities should not deter forensic probing. She noted that most of the victims in the Grim Sleeper killings were African American women.
The suspect in that case, Lonnie David Franklin Jr., was caught because the DNA left at a crime scene partially matched the DNA of his son, whose genetic information was filed when he was convicted of a felony weapons charge.
"It's a myth to suggest that poor communities, communities of color, don't want law enforcement," Harris said. "They do."
In reshuffling funds to double the number of familial searches to two a month, Harris said she was concerned that "some of the most serious and violent cases" were not being examined quickly enough.
In the Santa Cruz case, police arrested Elvis Garcia, 21, in March after a familial search identified him as the likely suspect and a subsequent DNA test of a Gatorade bottle and a hair net in his garbage matched the genetic evidence from the crime, authorities said.
The victim in the case "has been in utter fear every day since that crime that this rapist could come and find her at any time," Harris said. "Equally bad is that every day that rapist is walking free is a day he thinks he can get away with that kind of crime."