Investigators probing Laci Peterson's (search) disappearance had "about 41 reasons" why they believed her body had been dumped in San Francisco Bay, the lead detective assigned to the case testified Tuesday at Scott Peterson's (search) double-murder trial.

Modesto police Detective Craig Grogan ticked off a list that provided jurors with the first detailed narrative of the 17-week trial. And as he laid out the case, Grogan suggested that police had more than enough reason to focus suspicion on Scott Peterson.

Prosecutors allege Peterson killed his pregnant wife on or around Dec. 24, 2002, in their Modesto home, then dumped her body into the bay. Her remains and that of her fetus washed up in April 2003, not far from the marina where he launched his boat on Christmas Eve for what he claims was a solo fishing trip. Defense lawyers maintain someone else abducted and killed Laci.

Grogan's account had jurors leaning forward in their seats, scribbling notes as he made his points:

— "The dog tracking at the Berkeley Marina (search) that indicated Laci Peterson's scent was there."

— "The defendant told us that he was at the Berkeley Marina."

— "He had a two-day fishing license that was purchased on Dec. 20 and filled out for the 23rd and 24th."

— "The fishing tackle in the boat ... was freshwater tackle."

— Peterson told some witnesses on the night Laci vanished he had been golfing all day. "We considered that possibly that was what his initial alibi was meant to be."

— Peterson loaded large umbrellas into the back of his pickup truck that Christmas Eve morning. "It would enable him to be able to explain to anyone seeing him load something in his truck."

— Peterson had recently researched deep water currents in the bay, as well as information on some lakes in the area.

— "The fact that he paid cash for the boat and didn't register the boat."

Grogan then looked toward the jury as he summed up: "The ultimate conclusion was that Laci Peterson's body was in San Francisco Bay and that we needed to search there."

Despite these clues, Grogan noted that police remained open to other possibilities. "We had a policy that if someone called in and said they knew where Laci Peterson's body was ... that we would go there and search it."

Grogan also detailed a February 2003 search of the Petersons' home in which police discovered Peterson had packed bags ready for a trip. Stuffed in one pouch was his wedding ring, Grogan said. Police also found $2,081 in cash in the bags.

Grogan said detectives were looking for, among other things, "potential poisons."

Jurors were also shown part of a "Good Morning America" interview on Jan. 28, when Peterson told ABC's Diane Sawyer that he had told police about his affair with massage therapist Amber Frey on the first night Laci was reported missing.

In fact, Peterson didn't come clean with police about the affair — his motive, prosecutors allege, for the murder — until after he was confronted.

In a wiretapped phone call also played for jurors Tuesday, Peterson apologizes to Grogan for not being honest about the affair.

"They caught me answering a question about ... that I told you about a girlfriend ... is not true. We both know that," Peterson tells the detective, suggesting he had been caught off-guard in the interview.

On the taped call, Peterson soon begins to sob uncontrollably. "I'm losing it. I miss [Laci]. ... I'm just a mess without her," he says.

The detective then attempts to elicit a confession from Peterson, saying, "You and I both know what happened to Laci."

"Do you know what happened to her?" Peterson replies.

"We both do," Grogan says. "I want the door open between us. If you want to end all of this nonsense, all you need to do is call me, all right? We can sit down. I will not treat you badly. You can tell me what happened. We can get Laci back where she needs to be."

"I'm not involved in my wife's disappearance," Peterson insists, his sobs now replaced with a firm, steady voice. "We're going to find her."