Pretending he was dialing from Paris, Scott Peterson (search) sweet-talked Amber Frey (search) as she recorded his call, according to testimony the ex-mistress gave in court Wednesday.

In testimony interspersed with tapes of phone conversations, Frey told the court that she recorded the calls at the request of Modesto police after discovering that her lover was not only married, but suspected in the disappearance of his pregnant wife, Laci, on Christmas Eve in 2002.

In one conversation that took place Jan. 1 and was played to jurors, Frey asks Peterson, "So what, do you want to be together with me?"

"Well, I mean, obviously ... I think that we, you know, would be wonderful together," Peterson responds. "You know, in my mind we could be wonderful together and I could ... I could care for you in any and every way. For the rest of our lives."

The taped exchange took place the day after he called Frey "sweetie" and lied that he was standing near the Eiffel Tower, hearing fireworks in the middle of a huge New Year's crowd, when in reality he had just attended a vigil in Modesto for his missing wife.

Frey, a massage therapist who has become the government's star witness, testified Tuesday that she discovered Peterson had lied to her when a friend called her on Dec. 29 after seeing a news report about his wife's disappearance.

Frey said that their relationship had quickly progressed in two weeks from a hotel-room tryst after one blind date on Nov. 20, 2002, to something serious enough for her to trust him alone with her young daughter.

Peterson didn't wear a wedding ring and left her only his cell phone number after they met on a blind date. After their second tryst together, she gave him a car seat and the key to her house and had him pick up her 22-month-old daughter at day care.

The next day, they bought a Christmas tree together, decorated it and had sex again. It wasn't until Dec. 9 — three days after Frey's friend discovered he was married and confronted him — that he confessed to her that he had lied, and tearfully said he had "lost his wife," she testified.

At the time, Frey said she understood Peterson to mean that his wife was dead. "I thanked him for sharing that with me," she said, adding that she asked him if he still wanted to have a serious relationship with her. "He said, absolutely," she said.

Prosecutors appear to be trying to show that Peterson began hatching the murder plot at about this time — evidence shows he searched for used boats on Dec. 7-8, as well as numerous Web sites for fishing information, currents in San Francisco Bay and details on area boat ramps.

Prosecutors allege Peterson killed his wife in their Modesto home on or around Dec. 24, 2002, then drove to the bay and dumped her weighted body from a small boat he had purchased just weeks earlier. The badly decomposed remains of Laci Peterson (search ) and the couple's fetus washed ashore in April 2003, not far from where Peterson said he launched a solo fishing trip the day she vanished.

Frey has not been cross-examined — an opportunity the defense likely won't get for at least another day.

The Associated Press contributed to this report.