florida today in the case of casey anthony as defense attorneys for the accused child killer began their case in earnest this morning. and they attempted right away to tear apart the prosecution's evidence. an fbi examiner today testified that another fbi technician had contaminated the duct tape that investigators found near caylee's dead body and that it contained no d.n.a. evidence at all from anybody in the anthony family. the defense also attacked the prosecution's heart-shaped sticker theory. that sticker residue on the tape matched stickers that investigators found in casey anthony's bedroom. well, earlier in the trial another fbi forensics expert told the court that she had found an outline of a heart shaped sticker on one of the pieces of tape but that the heart had vanished. well, this afternoon on "studio b" i spoke with a forensic expert dr. michael baden. he said the judge should have never allowed the disappearing heart story in the first place.