MODESTO, Calif. -- A suspected burglar allegedly casing Laci and Scott Peterson's neighborhood in the early morning hours the day the pregnant Modesto woman was killed may be a key prosecution witness in the case, Fox News and other sources said Monday. According to the reports, one of two men arrested for a Dec. 26 burglary in the neighborhood -- Donald Pearce or Steven Todd -- has told police while casing the neighborhood he saw Scott Peterson doing something suspicious at around 3 a.m. on Dec. 24.

Peterson told KTVU's Ted Rowlands in a one-on-one interview in January that he thought someone saw him loading "large umbrellas" into his car the day Laci disappeared. Peterson said he was taking the backyard umbrellas -- wrapped in a blue tarp -- to a warehouse he used for his fertilizer business to store them during the wet winter months.

Police obtained a search warrant for the warehouse, but it was not known if they discovered the umbrellas in the building. Peterson currently is in Stanislaus County jail charged with two counts of capital murder for the deaths of his wife, Laci, and the couple's unborn son, Connor.

Peter Keane, dean of the Golden Gate University Law School, said a jury may have a hard time believing the burglar if he was put on the stand.

"(He's) not very credible," Keane said on Mornings On 2 Monday. "It will be brought to their (the jury) attention by the defense that this is someone who is in trouble himself and is probably trying to buy his way out of trouble by helping out police."

"Often times prosecutors can lose more by putting on someone like this and having them impeached very powerfully in front of the jury."

Sources also have told KTVU's Ted Rowlands that police believe that Peterson made two trips to the Berkeley Marina on Christmas Eve -- one early morning journey and another later in the day.

Peterson has produced a parking receipt from the marina as proof that he was there on a day fishing trip at the time Laci allegedly disappeared from the couple's Modesto home. He has told investigators when he arrived home later in the day, he found the couple's dog with a muddy leash running around the backyard, but Laci was nowhere to be found.

On Friday, Scott Peterson's attorney Mark Geragos told a judge he would produce several witnesses if a grand jury was held that would point the finger at another suspect in the killing of Laci Peterson and her unborn son, Connor.

At the end of a hearing in which Stanislaus County Superior Court Judge Al Girolami ordered the arrest and search warrants to remain sealed, Geragos stood and asked the judge to also rule that the Modesto County District Attorney's Office not be allowed to convene a grand jury in the case.

Instead, Geragos wants a more public preliminary hearing. The judge refused to grant Geragos' request and the defense attorney then pledged in open court to bring several witnesses to the grand jury that would point the blame at another suspect.

Outside the courthouse, Geragos went even further.

"We know there are people out there and specifically there is one particular young lady out there who we believe has some very important information," he said. "We are asking, and we will protect her anonymity, that she contact my office. We will do everything possible to keep you (the woman) out of this. Please provide us with the information we need."

Months of massive searches throughout Northern California failed to turn up any sign of Laci until her badly decomposed body washed up on shore near Point Richmond on April 14. The 27-year-old Peterson was eight months pregnant at the time of her disappearance.

The day before Peterson's body was found, the fetus of her unborn son Conner washed up on shore about a mile north. The bodies were found just north of the Berkeley Marina.

On April 18 police arrested Peterson in San Diego for the murders just hours before being alerted that the bodies of Laci and her unborn son had been positively identified through DNA analysis.

Modesto District Attorney Jim Brazelton has said he will seek the death penalty in the case.