Orlando (CNN) -- Tiny flies found in the trunk of Casey Anthony's car fit the theory that the body of her 2-year-old daughter was stored there, maybe for three to five days, an insect expert testified Saturday in the Orlando woman's capital murder trial.
The flies suggest something began to decompose inside the trunk, but do not prove that the material was a human body, said Neal Haskell, a forensic entomologist from Saint Joseph's College in Rensselaer, Indiana. Such flies will feed on many things, he said.
Based on his analysis of temperatures and the reproductive habits of the small flies found on paper towels that another scientist found were soaked in fluid from decomposition, Haskell said it appeared that whatever attracted the flies had been in the car for three to five days.
Defense attorney Jose Baez, in his cross-examination of Haskell, tried to show that the flies could have been attracted by common garbage or leftover food.
Haskell was the latest in a line of investigators and forensic experts called to the stand by prosecutors in an effort to prove their theory that Anthony, 25, killed her daughter by knocking her out with chloroform and taping her nose and mouth, putting the body in black garbage bags and storing it in the trunk before dumping her in woods near her home.
Anthony faces seven counts in her daughter's death, including first-degree murder, aggravated child abuse and misleading investigators. If convicted, she could face the death penalty.
She has pleaded not guilty. Her attorneys say Caylee was not killed but rather that she drowned in the family pool shortly after her family last reported seeing her and that Casey Anthony and her father, George Anthony, panicked on discovering the body and covered up her death. George Anthony rejected that scenario in his testimony the first week of the trial.
Saturday testimony also included a crime scene investigator who collected a piece of Henkel brand duct tape from an area near where Caylee's skull was found.
Ronald Murdock, a forensics supervisor for the Orange County Sheriff's Office, also testified that despite a thorough search of the house the only piece of Henkel duct tape investigators recovered from the home Anthony shared with her daughter and parents was attached to a gas can.
In testimony Friday. the chief medical examiner in the case said the way in which prosecutors say Caylee's body was discarded left no doubt that the girl was intentionally killed.
Earlier Friday, jurors saw graphic photos of Caylee's bones and heard testimony that they had been gnawed by animals as her body decomposed during as much as six months in the field.
They also watched a video superimposing an image of Caylee's skull over her living face and an outline of a strip of duct tape in an effort to prove tape could have been, in effect, the murder weapon, prosecutor Jeff Ashton said.
Baez tried to prevent jurors from seeing the presentation, which he called "disgusting." But Judge Belvin Perry ruled the role of duct tape in the girl's death is "highly relevant." He also rejected a defense motion for a mistrial based on the video at the close of Friday's session.
Earlier Friday, the chief medical examiner in the case, Dr. Jan Garvaglia, testified that Anthony's failure to report her daughter missing for more than a month was just one of three red flags that strongly indicate foul play.
The others were the discovery of the girl's remains amid black garbage bags in a wooded field -- "tossed in a bag to rot" was her testimony -- and the presence of duct tape on the girl's skull.
Saturday's testimony marked the end of the third week of the trial. Prosecutors have said they expect to wrap up their case next week. Initial estimates were for the trial, including the defense case, to be over by the end of June.
In Session's Nancy Leung contributed to this report.