Scott Peterson (search) looked for used boats on the Internet a day after a friend of his mistress confronted him about being married, prosecutors showed Wednesday, apparently hoping to convince jurors that the computer searches were an early step in a plot to kill Peterson's pregnant wife.

Scott Peterson also searched numerous Web sites for fishing information, currents in San Francisco Bay and details on boat ramps in the area, said Lydell Wall, an investigator with the Stanislaus County (search) Sheriff's Department.

Prosecutors allege Peterson murdered his wife, Laci, in their Modesto home 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 Scott Peterson said he launched a solo fishing trip the day she vanished.

Wall testified he examined five hard drives from computers seized from Peterson's home and office. He said he found that Peterson searched sales ads for used boats on Dec. 7-8, 2002.

Peterson had been having an affair with Amber Frey (search). Shawn Sibley, who introduced Peterson to Frey, testified earlier in the trial she confronted him Dec. 6 after learning he was married.

Wall said Peterson thoroughly researched how to fish for sturgeon and striped bass on San Francisco Bay. Peterson told police that's what he was fishing for the day his wife disappeared, but prosecutors say his gear was not suited for catching such fish.

Wall later testified that Peterson searched Web sites from the computer in the warehouse where he stored the boat prosecutors allege he used to dump Laci's body.

He said Peterson spent about 26 minutes on the computer on the morning of Dec. 24, 2002 — the same day prosecutors claim he disposed of the body.

On Tuesday, former Modesto police officer Kirk Stockham testified Peterson had researched water currents in the bay on Dec. 8, 2002, according to files he examined on Peterson's computers.

During his cross-examination of Stockham, defense lawyer Mark Geragos (search) noted a printout of the Web site Peterson visited regarding bay currents had different times and dates on it, one showing it was checked by Peterson Dec. 5 — a day before Sibley confronted him.

But on Wednesday, Wall testified that the date simply had not been updated by the Web site's manager. On cross-examination, he acknowledged the site also could have been viewed Dec. 5, saved on the computer and printed at the later date.

Geragos noted Peterson spent little time on Web sites involving bay currents, and mostly viewed fishing sites.

Also Wednesday, prosecution witness Gregory Reed, a family friend, testified Peterson called him the afternoon of Dec. 24, 2002, and never mentioned he'd been fishing, as he would later tell police.

Reed said Peterson called again later and left a "frantic" message: "Have you ... seen or talked to Laci today or yesterday?"

Later, Peterson cried as Reed recounted a time the two browsed a hunting catalog and spoke about how they both looked forward to buying gear for their children. Reed's wife was also pregnant at the time.

It was the first time in the 11-week-old trial Peterson has been visibly moved to tears.

On cross-examination, Reed acknowledged Scott and Laci appeared to be happy together and both were excited about being parents.