ORLANDO — Prosecutors have DNA tests and hair samples. They have testimony about "the smell of death" in the trunk of the suspect's car.
What they do not have is a body.
Prosecutors building a case against a single, 22-year-old Florida mother accused of killing her young daughter will have to rely on forensic evidence and convince a jury that Casey Anthony lacks credibility and had a motive, legal experts say.
Prosecutors have not been specific about how the evidence led to charges against Anthony, but experts say it is possible to get a conviction without a body, with several cases, including some in Florida, as examples.
"Sometimes circumstantial evidence is as powerful, or more powerful, than the body itself," said Donald Jones, a professor of criminal law at the University of Miami Law School.
Since 3-year-old Caylee Anthony's disappearance was reported in July, investigators have taken air samples from her mother's car trunk and tested for the presence of her DNA. Hair samples also have been analyzed.
The FBI and the Oak Ridge National Laboratory at the University of Tennessee performed the tests.
Charles Rose, a law professor at Stetson University College of Law in Gulfport, said the defense could contest the FBI findings for not being generally accepted.
Still, the use of forensic evidence has an increased credibility with jurors because of what he calls "the CSI effect" from the CBS television series, Rose said.
In the air tests used on Anthony's trunk, air is run into a carbon compound filter, such as activated charcoal, which collects the evidence, said Arpad Vass, a research scientist at Oak Ridge. Air flow is then reversed through the filter, releasing the compounds.
In this case, they were looking for compounds released when a body decomposes.
"We essentially turn into the dust from which we come," Vass said. "We return to the compounds which break down and blow off into the air."
Donald Jones, a professor of criminal law at the University of Miami law school, said the air tests, though likely admissible, probably won't help make a connection the prosecution is seeking. He said the tests only reveal the presence of the compounds, not their source.
The Anthony case also has other pitfalls, law professors say.
The defense could emphasize a lack of motive and blame others who could have kidnapped or killed Caylee. Prosecutors would need to give a jury a reason why a mother would kill her child.
Caylee was reported missing in July, but her mother told police she hadn't seen the girl since June.
Rose said the state has done a very smart thing in charging Anthony with murder and manslaughter, because it gives the jury a choice.
"You give the jury a place to run," Rose said.
Jury selection will be crucial, Jones said.
"Forget about reasonable doubt — if there's one mother in the stands she will wonder, 'How did she not know where her daughter was?' " he said.