…Continued from must-read Part I.
During DPD Michael Ogul's cross-examination of Samantha, she testified about her activity with boyfriend Manuel the night of her son Apollo's death:
Ogul: Did you and the defendant [Manuel] have sex that night?
Samantha: Just a blow job.
Ogul: Did he ejaculate inside your mouth?
Samantha: Yeah.
Ogul: What did you do after that?
Samantha: Went and cleaned myself off.
Ogul: What did you clean yourself up with?
Samantha: Baby wipes.
Ogul: And then what did you do with the baby wipes afterwards?
Samantha: Threw them away.
Ogul: Where did you throw the baby wipes away?
Samantha: I don't remember if I threw them in the trash can in my bedroom or if I threw them in the restroom trash.
"Was that really her testimony?", I asked Kulick. I now realized why Manuel's DNA was on everything, but Samantha on nothing. Her semen-covered hands had spread his DNA and masked hers!
Toddler Apollo had been in toilet training. His mother and primary caregiver Samantha had the defendant’s semen on her hands. Manuel's DNA swamped her own, as she handled the child. That's why forensic science couldn’t see her DNA anywhere.
Samantha had spread Manuel's semen everywhere: from her hands to baby wipes, to garbage bags, to whatever she touched—including Apollo. This artificial dissemination means we expect to see Manuel everywhere and Samantha nowhere. The DNA evidence had no probative value.
Pathologist Joseph O'Hara testified for the State about the rectal DNA he swabbed in Apollo's initial hospital examination. Deputy District Attorney (DDA) Lance Daugherty asked:
Daugherty: And in this particular investigation at the hospital, did you collect DNA swabbing from the victim’s anus?
O'Hara: Yes, sir.
Daugherty: And how did you do that?
O'Hara: The same way we did for his genitals. Swabs were broken from a sterile package, sterile water was applied. I would place the swabs around the skin of anus in a circular manner, insert an inch to two inches, pull them out, and then they would have been handed off to law enforcement.
Daugherty: Okay. So you never stuck the swab into the rectum or into the anus more than two inches?
O'Hara: Right. The beginning part of the anus and rectum is sufficient.
"That's it!", I exclaimed to Kulick. The doctor's anal swabbing had cleaned the boy's bottom of any residual DNA. And his internal "rectal" language was reporting external anal area findings.
Samantha had transferred Manuel's semen from her hands to Apollo's bottom when changing him. The first hospital swabbing collected and removed this external anal semen DNA. At autopsy, no semen remained. That's why the second “rectal” swab showed no DNA. Manuel's DNA wasn't in the child's rectum because there was no sexual assault.
But Kulick and I hadn't known all that when we'd prepared our trial materials. When I testified a few days later, we introduced these new exculpatory ideas for the first time. They were hard to convey.
Fortunately, a skeptical DDA Carolyn Powell hammered home my key points on cross-examination. Her questions let me explain more fully to the jury exactly why the DNA evidence didn't point to Manuel. Nor to anyone. So much DNA, so little evidence.
The lawyers gave marathon closing arguments. First, Daugherty argued for guilt and the death penalty. Then, for 7 hours, Kulick repudiated the state's forensic efforts. Using the TrueAllele results, and my semen transfer reasoning, Kulick proved there was no incriminating evidence. The jury agreed with her and the better DNA science. They acquitted Manual Lopez.
After California v. Lopez, Santa Clara County no longer seeks the death penalty. Kulick is now Judge Kelley Paul. Samantha was later convicted of child endangerment and being an accessory to murder.
I gave an hour-long talk at the 2021 American Academy of Forensic Sciences annual meeting on this case. The first half covered human bias in forensic science, so rampant in this capital case. The latter part showed how we found truth in the cautionary tale of California v. Lopez.
DNA Matters, an exclusive Forensic column, discusses cases that have been aided by the power of computer software in DNA analysis. It is authored by Dr. Mark Perlin, M.D., Ph.D., chief scientist, executive and founder at Cybergenetics. Twenty years ago, Perlin invented TrueAllele probabilistic genotyping for automated human identification from DNA mixtures. His company helped identify victim remains in the World Trade Center disaster, and has helped exonerate 10 innocent men. He is a Scholar in Residence at Duquesne University’s Forensic Science and Law program, and a Fellow of the American Academy of Forensic Sciences.