Just like Scott Peterson's in-laws, police were almost immediately suspicious after the fertilizer salesman reported his pregnant wife missing.

Within hours of responding to Peterson's home Christmas Eve, 2002, police summoned a detective -- an uncommon practice for a missing persons case, Modesto Police Sgt. Byron Duerfeldt testified Thursday during Peterson's murder trial.

"Based on what they told me I felt it was necessary to have a detective respond," Duerfeldt said.

Duerfeldt was stopped from explaining what the officers told him they saw in the home because he is not allowed to testify about what others said.

Prosecutors allege Peterson killed his wife, Laci, in their Modesto home, then dumped her body from his small boat on San Francisco Bay. His attorneys have speculated someone else abducted her while she walked the dog and have accused authorities of focusing too quickly on Peterson while ignoring other leads.

The remains of Laci Peterson (search) and her fetus washed ashore nearly four months later, just two miles from where Scott Peterson (search) claimed to have been fishing.

Duerfeldt was the first law enforcement officer to testify in the trial, which concluded its second week of testimony Thursday. If convicted, Peterson could face the death penalty or life in prison.

Earlier, Peterson neighbor Susan Medina testified about a burglary at her home after she and her husband left on Dec. 24, 2002, to visit family and returned two days later.

Defense lawyers have hinted the burglars may have been involved in Laci's disappearance. But prosecutors said the Petersons' dog was found wandering alone in the street before the Medinas left their home at midday -- indicating Laci disappeared before the break-in.

Police recovered much of the stolen property and arrested two men in the case, ruling out any connection to Laci's disappearance.

Medina later testified she saw nothing unusual in the neighborhood that morning.

"You didn't see anybody drag anything out of the house? You didn't see anybody load anything into a truck?" defense lawyer Pat Harris asked.

"No," Medina replied.

"You could see directly what's going on at the Petersons' house in the driveway?" Pat Harris asked.

"Correct," she replied.

Testimony was to resume Monday with additional police officers taking the stand.