Criminal
Aug. 3, 2002
Insect Debate Continues in Trial
SAN DIEGO - A forensic entomologist called by defense lawyers said Thursday that the body of Danielle van Dam was first exposed to insects at a time when defendant David A. Westerfield was under police surveillance.
Robert D. Hall, who teaches at the University of Missouri, said the body of the second-grader was exposed to blow flies between Feb. 12 and Feb. 23, and Hall said ants couldn't have carried off enough fly eggs and larvae to make any difference in his calculations.
"If ants were that effective, then we'd no longer have blow flies because the ants would have eaten them all," Hall said on direct examination by defense attorney Steven E. Feldman.
But on cross-examination by Deputy District Attorney Jeff B. Dusek, Hall said he had written scholarly articles with a forensic entomologist who testified earlier for the defense and came to almost identical conclusions while using a different method of calculation.
Hall also said he thought the words "mean" and "median" both meant "average," and under aggressive questioning by Dusek, he conceded that he confused the terms while criticizing a fellow forensic entomologist who testified for the prosecution.
As the trial neared its end, Westerfield's defense team called Hall in reply to the prosecution's rebuttal witnesses, who had attempted to offset defense testimony.
That testimony was given as part of an attempt to create doubt about whether the 50-year-old self-employed engineer could have left Danielle's body where it was found beside a rural road east of El Cajon.
Westerfield is charged with kidnapping and murdering 7-year-old Danielle, whose parents discovered early Feb. 2 that she had vanished from her upstairs bedroom. A search of the neighborhood began almost immediately, and Westerfield alone among the neighbors was not at home. When he returned Feb. 4, he told police he had driven a meandrous route in his motor home across San Diego County to the desert in Imperial County and back. He was arrested Feb. 22 and has been held without bail since then. He faces the death penalty if convicted.
Danielle's nude body, decomposed and partially eaten by animals, was found by volunteer searchers Feb. 27. Because of the body's condition, the medical examiner was unable to determine how she died and whether she had been sexually assaulted.
Feldman said during his opening arguments June 4 that science would prove Westerfield did not kill Danielle, apparently referring to planned testimony by two forensic entomologists. The two, David Faulkner and Neal Haskell, testified that, based on the stages of blow fly larvae found in Danielle's body, the body was exposed to the flies two weeks after she vanished.
The prosecution replied with testimony from a forensic anthropologist, William Rodriguez, who specializes in bodily changes after death, and a forensic entomologist, M. Lee Goff.
Rodriguez said that mummification of Danielle's body reduced the access of flies because they need a moist place to deposit the eggs and that the larvae need moisture to grow. Goff said temperatures at the site where Danielle was found among old tires, engine blocks, bedding and beer cans were low enough early in February to inhibit flies that normally would have colonized the body within minutes or a few hours.
Rodriguez also said that if animals partially ate Danielle's abdomen, they would have exposed moist areas to flies, which could have arrived much later than when the body was left beside the road.
Both men put the point when Danielle's body was first exposed to the flies at the time Danielle disappeared.
Hall said under questioning by Feldman that the testimony by Rodriguez was "inconsistent with the insect evidence I've examined."
Hall also said he had never heard of a partially mummified body being opened by animals and then colonized by flies.
He had never seen a situation where an "individual had dried out so quickly that the insect activity was the product of a subsequent opening by a scavenging animal."
He also said on direct examination that Goff's calculation method - which calculated total heat needed for the larvae in Danielle's body to grow to the size they had reached when the body was found - assumed that temperature rose and fell in a uniform manner.
"That is not the way temperatures work in the real world," Hall said.
He also said that he had found "arithmetic mistakes" in Goff's report.
During cross-examination, Hall said he used, as Goff did, daily high and low temperatures to reach an average and then calculated "accumulated degree days." Goff used "accumulated degree hours." Both methods assume a uniform rise and fall in temperatures.
When calculating what Hall called arithmetic mistakes by Goff, Hall wrongly believed that Goff's use of "median" temperatures in a report on the case meant that he had wrongly calculated average temperatures, the entomologist testified under questioning by Dusek.
Hall said he had co-written four scholarly papers with Haskell, the earlier defense witness, and the two men have two other articles under preparation. In addition, he said, Haskell when preparing for his testimony sent Hall flies so that Hall could confirm their identity.
And he said under questioning by Dusek that if a barrier to insects, such as mummified skin, was opened by animals, then the newly exposed flesh would be attractive to flies.
San Diego County Superior Court Judge William D. Mudd told the jury late Thursday that no testimony will be heard today and that court will not be in session Monday. But, he said, on Tuesday the defense may call a final witness. He also said closing arguments will begin either Tuesday or Wednesday.
Claude Walbert
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