in the cases where it did happen, it was reversed. >> reporter: after days of calling walter quijano,racked him down at his clinic. hi, i'm with cnn. we have been trying to get ahold of you to talk about your testimony in several death penalty cases. >> sure. >> he invited us in. he said to clear the misconceptions over his testimony. he says over the years, he's received death threats. >> the allegations that, allegations that you are a racist, allegations that are you you are a racist and your testimony is racist, what do you say to that? >> well, it's not true, but, okay, i have never been that type of person who will argue for me. >> reporter: he says his testimony has been misunderstood. he argues that some 20 social factors can be used to determine if someone is likely to repeat violent behavior, things like age, sex, socioeconomic background. education, drug use, yes, race. >> they pick that one piece of testimony and twists it and makes it look like race causes people to make crimes, which is stupid. now, no human being would say such thing. >> reporter: in some of the testimo