Traces of chloroform were reportedly found in the trunk of a car driven by the mother of missing toddler Caylee Anthony, a Florida newspaper has reported.
The Orlando Sentinel, citing unidentified sources, said that preliminary FBI tests found the chemical in Casey Anthony's car trunk. Law enforcement sources had previously told ABC News that air-sample tests from the trunk found evidence of human decomposition.
The paper also reported that there was evidence that Anthony may have searched for information about the chemical on her computer.
Chloroform, once used as an anesthetic, can cause a person to pass out. High doses can be fatal.
For more exlcusive photos and home videos of Casey and Caylee Anthony, watch "20/20" Friday at 10 p.m. ET.
Anthony, 22, called a "person of interest" in the disappearance of her daughter, Caylee, is being held in the Orange County, Fla., jail on charges including child neglect and making false statements. She has not been charged in connection with Caylee's disappearance.
Calls to Casey Anthony's lawyer by ABC News weren't immediately returned.
Police have been searching for Caylee since July, and the Orange County sheriff's department has said that it believes she is probably dead. Anthony has given the police changing and inaccurate information about the case, according to investigators.
Police last month said hairs the same length and color as Caylee's were found in the trunk of the car, and Casey Anthony's mother, Cindy Anthony, said in a 911 call in July that the car smelled like there had been a dead body in it.
Cindy Anthony has since retracted those comments, saying the smell could easily have been from garbage in the car.
Last weekend, Anthony was sent back to jail on new charges, including petty theft and use of a forged check. The $500,000 bail, posted by a California bondsman that released Anthony from jail, was also rescinded.
On Wednesday, the sheriff's office charged her with additional check fraud and theft counts.