A second forensic expert testified Monday that insect evidence indicates Danielle van Dam's body was dumped along a San Diego road side after murder defendant David Westerfield was already under police surveillance.

The expert, Indiana forensic entomologist Neal Haskell, told jurors that the age of the flies and maggots found on the 7-year-old's body indicate that the girl was likely left along the highway between Feb. 12 and Feb. 21.

Danielle was kidnapped from her bedroom the night of Feb. 1 and police began constantly monitoring Westerfield, her 50-year-old neighbor, four days later.

Danielle van Dam

The conclusions of the two entomologists are the defense's strongest evidence for Westerfield's innocence. Defense lawyer Steven Feldman told jurors during opening statements that "science" would rescue Westerfield by proving it was not physically possible for him to be at the site at the precise time her body was dumped.

Entomologist David Faulkner testified earlier in the defense case that infestation likely occurred between Feb. 16 and Feb. 18.

"He had a narrower time frame than me," Haskell said when pressed on the disparity by prosecutor Jeff Dusek. "I was being more conservative."

Forensic entomologists cannot testify as to the time death occurred, but can estimate the time a dead body was first colonized by insects. Infestation can occur as soon as 20 minutes after death, but could take longer depending on the climate and whether the body has been covered, experts say.

Prosecutors, who have amassed a pile of other forensic evidence linking Westerfield to the kidnapping and murder, are taking the entomological challenge to their case very seriously. They have hired at least one insect expert, M. Lee Goff of Hawaii, to reanalyze the evidence. Goff and Haskell squared off in another case, the murder trial of Thomas "Zoo Man" Huskey, a serial killer in Tennessee.

In his cross-examination, Dusek suggested Haskell did not take into consideration the strange weather in San Diego in February when making his calculations. Faulkner testified that hot, dry and windy conditions reduced the fly population to the lowest levels ever noted, but said flies were still present. Haskell largely downplayed the abnormal climate, saying the insect life recovered from the body proved flies were still abundant at the scene.

At one point, Dusek asked Haskell if he had considered whether Danielle's dead body might have become mummified while driven around hot desert areas in Westerfield's recreational vehicle for a day and a half before being dumped along the road. Haskell admitted that the body might mummify slightly in such a scenario, but "not to the extent that it would inhibit the blowflies."

The prosecutor also quizzed Haskell about whether bleach perhaps used by the killer to wipe evidence from Danielle's body might repel insects. Detectives found an empty bleach bottle in Westerfield's garbage and the cleaner was at the top of a grocery list found in his house.

Haskell said he was not sure of the effect and was not aware of any studies on the subject. Before testimony began, Judge William Mudd warned jurors that the abduction and slaying of 5-year-old Samantha Runnion in Orange County had nothing to do with the case they were hearing.

"Other matters in other locations are of no relevance to the case," said Mudd.

There will be no testimony in the case Tuesday because of a hearing concerning the prosecution's rebuttal witnesses.