Tuesday, June 17, 2008
S.C. Upholds Conviction Based on ‘Cold’ DNA Hit
By SHERRI M. OKAMOTO, Staff Writer
Evidence establishing the likelihood of a defendant having committed a charged crime, expressed as a probability that a person selected at random from the relevant population would have a DNA profile matching the evidentiary sample taken from defendant, was admissible in a “cold hit” case, the California Supreme Court ruled yesterday.
A unanimous court upheld Dennis Louis Nelson’s conviction for the 1976 rape and murder of a Sacramento teenager, concluding that the use of the “product rule” to calculate the odds in a cold hit case was not a new scientific technique subject to the Kelly test, and was admissible on relevance grounds. .
The product rule is a statistical method to calculate the rarity of a given DNA sample in the relevant population, expressed as the probability of a single random person possessing the same DNA profile as the person whose DNA was found at a crime scene.
At trial, over objection, the prosecution presented evidence that the DNA profile on the victim’s vaginal swab would occur at random among unrelated individuals in about one in 950 sextillion African-Americans, one in 130 septillion Caucasians, and one in 930 sextillion Hispanics. The body of the victim, Ollie George, was found in unincorporated Sacramento County two days after she failed to return home from a visit to a local shopping center.
She had been raped and drowned in mud. Nelson was questioned by police shortly after the crime, when a witness told police that he had seen a car in the area, believed it was the same car in which he saw a woman matching George’s description at the shopping center the day of her disappearance, and took down the license plate number.
The car belonged to Nelson, who gave police what the Court of Appeal caled a “confused” explanation of his whereabouts on the night of the crime. He was not charged at the time, but later went to prison for other offenses, including rape, and had his genetic profile entered into the state’s DNA database.
He was charged with the George killing in 2002, after the Legislature appropriated funds to match DNA samples taken from the scenes of unsolved crimes to those in the database. The defense contended at trial that he and George had consensual sex the weekend before she disappeared, but that he was not involved in her killing and disappearance.
A jury convicted Nelson of first degree murder, and the Third District Court of Appeal affirmed.
Nelson argued that the product rule could not be applied in cold hit cases because it presupposes a randomly selected person. Thus, he contended, when a suspect is found by a search of a DNA database the chance of a coincidental match is increased.
Writing for the Supreme Court, Justice Ming W. Chin noted that the product rule has “‘gained general acceptance in the relevant scientific community,’” and therefore reasoned that a full-fledged hearing on the validity of the product rule was not required by People v. Kelly (1976) 17 Cal.3d 24.
Kelly holds that proponents of evidence based on new technology must show that the methodology has achieved general acceptance in the relevant scientific community, establish the qualifications of the expert testifying, and prove the procedures were correctly employed.
Although there are other methods for calculating the significance of a match that do not exist when a sole suspect is compared to the crime scene evidence, Chin explained, Kelly does not require that there be only one approach to a scientific problem.
Further, Chin reasoned, the odds calculated by the product rule are relevant in a cold hit case. “It remains relevant for the jury to learn how rare this particular DNA profile is within the relevant populations and hence how likely it is that someone other than defendant was the source of the crime scene evidence,” he wrote.
Chin also concluded that the justification for the “purely investigative” 27-year delay in prosecuting Nelson outweighed the “minimal” resulting prejudice, so that the delay did not violate Nelson’s constitutional rights to a fair trial and due process.
“If modern DNA technology and statistical methods had existed [in 1976],” Chin suggested, “law enforcement authorities might have compared [Nelson’s] DNA to the crime scene DNA and applied the product rule to obtain the same results ultimately obtained after the database search that actually occurred.”
The issue, Chin explained, was one of due process rather than the right to a speedy trial, because the latter right is not triggered until the defendant is charged and Nelson did not contend that there was an unreasonable post-charging delay in bringing him to trial.
Chief Justice Ronald M. George and Justices Joyce L. Kennard, Marvin R. Baxter, Kathryn Mickle Werdegar, Carlos R. Moreno, and Carol A. Corrigan joined Chin in his opinion.
The case is People v. Nelson, 08 S.O.S. 3487.
Copyright 2008, Metropolitan News Company