A judge sealed more court documents in the Laci Peterson (search) murder case Friday after prosecutors said the investigation was ongoing and claimed that revealing evidence would jeopardize her husband's chances of getting a fair trial.

Judge Al Girolami sealed court papers that contained evidence police used to get a warrant to arrest Scott Peterson (search) and to conduct another search after his arrest.

In legal briefs filed Thursday in Stanislaus County Superior Court (search), police said the affidavits they had filed outlined evidence in the case and named witnesses. They said revealing that information could hurt their investigation as they follow up on 9,000 tips in the case.

Girolami sealed the papers and said he would reconsider motions by three California newspapers to unseal them at a May 27 hearing.

The search warrants, affidavits supporting them and lists of items seized are expected to contain a summary of evidence compiled in the case of the missing 27-year-old pregnant substitute teacher who vanished just before Christmas.

Scott Peterson, 30, said he saw his wife Dec. 24 as he left to go fishing in Berkeley. Her body and the remains of her unborn child washed ashore in San Francisco Bay last month near where Peterson claimed he was fishing.

Peterson has pleaded innocent to two counts of murder and faces the death penalty if convicted. He is being held without bail.

Police have searched the couple's house, the storage warehouse where Peterson, a fertilizer salesman, kept supplies, and seized his boat, truck and trailer. They also used a search warrant to get a DNA sample from Peterson.

Following court-approved searches, certain paperwork must be returned to the court and made public unless a judge seals them. In this case, nine search warrants have been sealed. The Modesto Bee, the Contra Costa Times and the San Jose Mercury News have argued that the court papers should be made public.