Danielle van Dam was dead at least a month before rescuers found her remains, according to a military scientist who specializes in the decomposition of bodies.

Testifying Thursday in the San Diego murder trial of David Westerfield, prosecution witness William Rodriguez III, a forensic anthropologist at the Armed Forces Medical Examiner's Office, added yet another layer of confusion to the mass of testimony about when Danielle was murdered.

In the final days of Westerfield's two-month long trial, the timing of her killing has become the central issue. Two forensic entomologists for the defense said insect evidence from Danielle's corpse indicate she was dumped on a roadside in mid-February, long after Westerfield was under police surveillance. Danielle went missing Feb. 1, and Westerfield became a suspect a few days later.

In his closing argument, scheduled for next week, defense lawyer Steven Feldman is expected to argue for an acquittal largely on his experts' findings about time of death.

In their rebuttal case, which began Wednesday and will continue into next week, prosecutors are trying to discredit the conclusions of those defense experts and get jurors to focus on the pile of largely unrefuted forensic evidence, including fingerprints and blood drops, linking the defendant to the crime. In addition to Rodriguez, prosecutors plan to call their own forensic entomologist, M. Lee Goff.

Rodriguez, who studied the remains of American casualties in Operation Desert Storm and the Balkans, did not directly dispute the defense entomologists' interpretation of maggots and flies. Instead, he suggested that the exterior of Danielle's body quickly mummified and that drying skewed the normal clues the experts use, such as the size and abundance of the bugs, so much as to be irrelevant.

"The tissue becomes so hard that larvae cannot penetrate them. They won't feed on them," said Rodriguez.

He said photos of Danielle's body at the dump site and during her autopsy indicated "rapid mummification," a condition he attributed to hot, dry winds and the small size of the victim's body.

Danielle van Dam

But Rodriguez acknowledged under cross-examination that the time frame he estimated — four to six weeks before her body was found — missed the day of her abduction by 24 hours and spanned a period where Danielle was alive.

Rodriguez said Danielle died sometime between Jan. 16 and 31. She disappeared from her home the night of Feb. 1 and her naked, decomposed body was found Feb. 27.

"This is all speculation, isn't it?" asked Feldman. Judge William Mudd ordered the witness not to answer. Prodded later by prosecutor Jeff Dusek, Rodriguez said she could have been killed any time in the first week of February.

Defense lawyer Feldman also got Rodriguez to acknowledge that the San Diego medical examiner, Dr. Bryan Blackbourne, was well respected and more familiar with the area's weather and its effects on decomposition. Blackbourne said Danielle died sometime between Feb. 1 and Feb. 18.

Feldman's cross-examination revealed that a nationally known forensic pathologist, Cyril Wecht, whose famous cases include the Ted Binion murder in Las Vegas, consulted for the prosecution and agreed with Blackbourne's findings.

Testimony in the case resumes Tuesday. On Monday, the judge will meet with lawyers to discuss jury instructions and closing arguments.