Oswalt said under cross-examination that the hair came from two separate sources and that he could not decisively determine whether either hair came from Laci because the strands did not have roots. He also said the hair did not belong to Peterson. Another prosecution mitochondrial DNA expert said tests concluded that at least one of the hair fragments belonged to Laci. But the defense disputed the validity of the tests because mitochondrial DNA analysis is less precise.
Geragos also got a prosecution criminalist to concede repeatedly that investigators found no blood or any other kind of physical evidence on Peterson's boat or in his home linking him to Laci's slaying. And he put prosecutors on the defensive with allegations that investigators focused primarily on Peterson in his wife's disappearance and neglected other leads and theories.
In the last part of the prosecution's case, Geragos also enabled jurors to learn through the testimony of the lead investigator in the case that Peterson had multiple extramarital affairs. This, Geragos suggests, proves that Peterson would not have killed Laci to continue his affair with Frey.
To win a conviction, prosecutors will have to use closing arguments to stress Peterson's suspicious behavior at the time of his arrest, his many lies and the alibi that places him near where the remains of Laci and their unborn son were ultimately found. The defense will have to focus on the lack of physical evidence tying Peterson to the slayings to gain an acquittal -- or at least a hung jury.
"The bottom line is that there isn't much physical evidence at all connecting Scott Peterson to this case," California defense attorney Steve Cron has said. " He [Geragos] may say something like, 'It's OK that you don't like my client. That's fine. But at the end of the day, can you honestly leave here and say the evidence shows he murdered his pregnant wife?'"
Both sides are expected to give closing arguments in Peterson's trial next week. Right now, it seems the prosecution may have momentum on its side.
"This case is ripe for a hung jury, but more likely now that the prosecution will be able to obtain a conviction [rather] than an acquittal," said Guilfoyle Newsom. "And that's saying something. It didn't look like that in the beginning."