"I'm not an evil guy," Peterson said on tapes played in court Monday. "I lied to you ... but I'm not an evil person."
Judge Alfred A. Delucchi said last week that the tapes would continue to be used through Tuesday morning. Defense attorneys said they expected to begin their cross-examination of Frey by Tuesday afternoon.
On Monday, jurors heard Frey pressing Peterson on how she could ever trust him.
"I can only hope that that's a possibility," Peterson tells her. "We can have a relationship."
Monday was the fourth day jurors listened to the recordings, taped by Frey at the request of police in the days after the pregnant Laci Peterson vanished.
Prosecutors allege Peterson killed his wife in their Modesto home on or around Dec. 24, 2002, then drove to the San Francisco Bay and dumped her weighted body from a small boat he had purchased weeks earlier. The badly decomposed remains of Laci Peterson and the couple's fetus washed ashore from the bay in April 2003, not far from where Peterson said he launched a solo fishing trip the day she vanished.
His defense attorneys claim he was framed after the real killer learned of his widely publicized alibi.
Authorities hope to show jurors that Peterson's motive for killing his wife and their unborn child was to be with Frey.
Frey has testified that she called police after discovering her lover was not only married, but suspected in the disappearance of his pregnant wife. Officers asked her to record Peterson's calls.
At one point, as Frey presses him about hiding the affair, it appears as if Peterson accuses her of being involved in Laci's disappearance.
"You know, Scott, when people find out (about the affair), and they will, no one will think your behavior is innocent," Frey says.
"I had nothing to do with this ... and I just, you know, I hope that you ... are not ... involved to any degree," Peterson replies.
"How ... back up! ... Back up to that statement," Frey says angrily.
"You know, what I mean by that is obviously you're not involved ... but I mean I don't want ... you to have any repercussions from people," Peterson says.
Frey took the witness stand twice Monday morning simply to affirm that the tapes were made by her. She remained in court the rest of the time.
Like a detective, Frey pressed Peterson for answers on the tapes, interrogating him about what he and Laci had done the day before she vanished.
Peterson said they ate pizza and watched a movie, "The Rookie," before going to sleep. Frey asked him if they slept in the same bed.
"Amber, please don't ask ... I can't ... I can't tell you these things," Peterson says. "I can't tell you everything right now."
Peterson maintains he told Laci about his affair with Frey after the pair's first date.
"Are you telling me Laci was OK with me?" Frey asks.
"Yeah," Peterson says.
"That's really hard for me to believe," Frey replies, before calling him a "pathological liar."
The recorded phone calls also contain references to the Bible and "Romeo and Juliet," reports Reporter Gloria Gomez of CBS News' Sacramento station KOVR.
Former prosecutor Wendy Murphy told the CBS News Early Show that Frey is "coming across as another victim of Scott's."
"I think this evidence really is probably the most damning against Scott, because it shows him not only to be a cad and a liar, but the kind of guy who could kill his pregnant wife. That's crucial for the prosecution," said Murphy, who believes Peterson knew he was being taped and avoided saying anything directly incriminating.
But defense attorney Mickey Sherman told the Early Show the tapes were but "mildly interesting" and "sleazy on both sides."
"They're both kind of b.s.-ing each other, but it gets nowhere towards moving the ball forward … Everybody who cheats on their wife or husband doesn't become a murderer," Sherman said. "There are no confessions in there."