Casey Anthony's lead defense attorney sprang a surprise at her murder trial on Thursday by questioning whether Casey's brother Lee could be the father of her 2-year-old daughter Caylee, who was found dead in 2008.
Judge Belvin Perry immediately dismissed the jury after defense attorney Jose Baez posed the paternity question on the first day of the defense presenting its case after 3 1/2 weeks of prosecution witnesses.
After the jury left for the early lunch break, a testy argument erupted between attorneys over the appropriateness of the question.
FBI expert Heather Seubert told the judge that DNA samples from both Lee and George Anthony, Casey's father, were tested and excluded them as possible fathers of Caylee.
During his opening statement last month, Baez claimed that Casey had been molested by her father and that Caylee had drowned in the family's swimming pool.
On Thursday, Perry chided Baez and asked him to read up on case law on "good faith questions."
Prosecutors accuse Casey, 25, of killing Caylee on June 16, 2008, storing the child's body in her car trunk, and then dumping it in woods near her home.
Caylee was reported missing on July 15, 2008, after Casey's car was found in an impound lot and her mother Cindy Anthony described it as smelling of death. The child's skeletal remains were found in woods near the Anthony family's home on December 11, 2008 after a nationwide search.
DNA and blood tests on material from Casey's car trunk and clothing, as well as from duct tape found on and near Caylee's skull were the focus of much of Thursday's testimony by three expert witnesses from the FBI.
Seubert, the FBI's DNA expert, testified that no blood or DNA of any significant amount was found on any of the material she tested.
Prosecutor Jeff Ashton replied: "The absence of blood doesn't mean the absence of crime."
He asked Seubert whether the lack of blood or DNA in the trunk could be explained by a body having been wrapped in plastic. She agreed that a plastic bag or other protective material could have prevented material from leaking.
DNA contamination was another focus on Thursday.
A tiny bit of DNA material found on the duct tape was determined to belong to FBI document analysis expert Lorie Gottesman. The tape had been sent to her to see if she could find any evidence of a heart-shaped sticker.
Another FBI examiner previously testified to having seen the outline of a small heart on the duct tape prosecutors say Casey used to smother her daughter.
The defense pressed Seubert and the other FBI witnesses on Thursday about quality control at their labs. Gottesman testified she had taken great care in the handling of the tape and had no idea how her DNA had contaminated the item.
She also said she had used special visual enhancement tools to examine the tape and found no evidence of a heart-shaped sticker or sticker residue.
Three Orange County Sheriff's crime scene investigators testified about items found in the woods near Caylee's remains. A photo of a heart-shaped item on a piece of stained cardboard was introduced into evidence, along with photos of bags of trash gathered from the search.
Crime scene investigator Robin Maynard said the heart-shaped item was found approximately 45 feet from the skull. The prosecution had previously shown photos of many heart-shaped stickers from Casey's bedroom, none of which resembled the heart-shaped item found on the ground.
Prosecutor Linda Drane Burdick asked whether it would be fair to describe the area where Caylee's body was found as a trash dump. The crime scene investigator said yes.
The defense case will continue at 9 a.m. on Friday.