Defense: Laci Poisoned?

Investigators in Laci Peterson's disappearance once considered the possibility the pregnant schoolteacher was poisoned to death by her husband to explain the absence of a bloody crime scene, according to testimony Tuesday.

Defense attorney Mark Geragos, who has sought to discredit the investigation into Laci's death, asked lead Detective Craig Grogan if at one point investigators theorized that Laci had been poisoned -- a theory that never panned out and has not been presented by prosecutors in court.

"Yes, we looked into that," said Grogan, who has been on the witness stand for more than a week.

Prosecutors allege Scott Peterson killed his wife in their Modesto home on or around Dec. 24, 2002. Grogan, a prosecution witness, said police considered the poison theory because they were unable to find any signs of a struggle and found none of Laci's blood in the home.

Grogan testified that during a Feb. 18, 2003, search of the Petersons' home that police seized a mortar and pestle to examine them for the existence of any drugs. None was found, he said.

Prosecutors allege Peterson killed Laci, then dumped her weighted body into San Francisco Bay. Her remains — and that of her fetus — washed up in April 2003, not far from where Peterson launched his boat that Christmas Eve morning for what he claims was a solo fishing trip. Investigators have not determined the cause of death.

Peterson's lawyers maintain someone else abducted and killed Laci while she walked the couple's dog in a nearby park. The dog was found by a neighbor in the street the morning Laci vanished, according to previous testimony.

On Tuesday, defense lawyers sought again to attack the police investigation as incomplete and narrowly focused on Scott Peterson, pointing out inconsistencies in police reports and testimony and failures by detectives to follow leads.

Geragos noted that Grogan had consulted early in the investigation with an expert on tidal action in San Francisco Bay.

The expert, Geragos said, theorized that the 30 pounds of cement prosecutors allege Peterson used to sink his wife's body in the bay would have been too light to keep her pregnant body down.

Grogan then acknowledged that police also theorized that Peterson had wrapped Laci in plastic before dumping her in the bay, but the expert told him her remains would likely have been found in much better condition.

Geragos also revisited the issue of whether the fetus was born alive, which defense lawyers claim was the case, and shows Scott Peterson was not the killer. Prosecutors say the fetus was expelled from Laci's decaying body.

Grogan acknowledged that a medical examiner had found some evidence that the child may have been born alive.

Geragos also brought up Peterson's own frustration with authorities as they focused on him, a point defense lawyers have suggested caused police to ignore other leads.

"He told you you had been wasting time investigating him rather than following up on leads in the case?" Geragos asked.

"That's correct," Grogan said.

The judge has said the prosecution would not wrap up its case this week as previously intended.