Forensics expert starts 3rd week of Anthony trial

By the Associated Press | June 6, 2011 | 10:14 AM EDT

ORLANDO, Fla. (AP) — Casey Anthony's trial in the death of her 2-year-old daughter entered its third week with the start of what is expected to be lengthy forensics testimony.

Arpad Vass, a researcher at the Oak Ridge National Laboratory, was the first witness called Monday. Vass has pioneered a novel technique for detecting human decomposition from air samples.

Prosecutors are trying to prove that Anthony suffocated her daughter, Caylee, with duct tape in 2008 and contend that traces of decomposition were found in her car.

Anthony has pleaded not guilty. Her defense attorney says the toddler drowned in her grandparents' swimming pool.

If convicted, the 25-year-old Anthony could be sentenced to death.