Many (if not most) trial observers believe that accused murderer Casey Anthony is indeed guilty of killing her two-year-old daughter Caylee.
Some of the physical evidence against her is less than overwhelming, however, according to a Casey Anthony defense witness testifying today.
The air in Casey Anthony's car trunk contained chemicals associated with human decomposition, but didn't conclusively prove a body was there.
Dr. Michael Sigman, a professor at the University of Central Florida, said Casey's trunk showed traces of gasoline, chloroform and other chemicals.
However, those readings were all low, and said chemicals also are linked to onions, cabbages and Clorox, among other things. So ... it's tough to say.
As a result, Sigman told attorney Cheney Mason, "I cannot conclusively determine that there had been human remains in the trunk of the car."
This comes after prosecutors strongly suggested there were.
Prosecutors in the murder trial in Orlando had called several experts who concluded that based on the air samples, a strand of hair, insect activity and the reaction of cadaver dogs that a body was in fact in the Florida mom's car.
Among several other witnesses who took the stand at the trial today was Madeline Montgomery, a forensic toxicologist for the FBI.
She testified that she found no evidence of drugs – including calming medications Xanax and Valium – in hair presumed to be Caylee Anthony's.
But she also acknowledged she could not test the hair for chloroform, which was one of the ways prosecutors say Caylee was murdered.
Casey Anthony, 25, faces the death penalty if convicted.
What do you think? Is she ...