Dr. Michael Rickenbach, who works for the FBI, said he was "surprised" to find the chloroform residue because the chemical is volatile and dissipates quickly. He said he found chloroform residue on a spare tire cover and signs of a chemical that could be chloroform on the trunk liner.
Anthony, 25, is charged with murder in the death of her 2-year-old daughter, Caylee, who vanished in June 2008. The child's skeletal remains were found months later in a swampy area near her grandparents' house in Orlando.
The prosecution suggests Anthony used duct tape and chloroform to kill her daughter. Investigators found evidence someone at George and Cindy Anthony's house searched online for information on chloroform before Caylee's disappearance.
Earlier Tuesday, Gerardo Bloise, a crime scene investigator with the Orange County Sheriff's Office, described a bag of trash found in the trunk of Anthony's Pontiac Sunfire. He said the contents of the bag smelled like "normal trash" while the trunk had a sharper smell.
Prosecutors say Caylee's body was kept in the trunk for some time.