MODESTO - The Contra Costa County Coroner's Office could not determine a cause of death for Laci Peterson, but concluded that her son was born dead.

The coroner lists Peterson's manner of death as homicide. Death certificates for the 27-year-old and the son with whom she was eight months pregnant were made public late Friday.

A judge agreed earlier in the day to allow release of the documents, but kept sealed the results of the two autopsies.

During two hours of courtroom wrangling, Stanislaus County Superior Court Judge Al Girolami told Scott Peterson's defense lawyers and the prosecutors who have charged him with the murders of his wife and child that the report will remain sealed until a preliminary hearing.

The death certificates were filed in Contra Costa County on Friday. Signed April 21, they are the official record of Laci and Conner Peterson's deaths.

The filings do not mean the remains will be released to Laci Peterson's family. A court order requires the coroner's office to retain custody of the remains until told otherwise by a judge, said coroner's spokesman Jimmy Lee.

Laci Peterson's family does not know when that will be, said family spokeswoman Kim Petersen. "It's a very tough time for them," she said Friday.

The death certificates contain the time and place of death. For Laci Peterson, the coroner's office specifies the date she was found on the Richmond shoreline, April 14.

Conner Peterson was found a day earlier. That is specified on his fetal death certificate, along with where he was found along the Richmond shoreline. Fetal death certificates have no category for a cause of death. Conner's does specify that he was born dead.

Cable news station MSNBC reported last week that a leaked portion of the autopsy reports showed that Conner was found with 11/2 loops of tape around his neck.

Legal analysts have surmised the information could be used to back a defense theory that a satanic cult played a role in Laci Peterson's disappearance and slaying.

It also was widely believed that the defense team had a hand in leaking the autopsy to bolster its case with the public, an allegation attorney Mark Geragos adamantly denied.

The autopsy had been sealed May 15 at the request of both defense attorneys and prosecutors. After last week's leak, the Stanislaus County District Attorney's Office asked that the entire report be unsealed.

Deputy district attorney David Harris told Girolami on Friday the leaked details provided a "significant slant" in favor of the defense. "We can't discuss inaccuracies or accuracies without violating the court order," he said.

Girolami said the results will not be unsealed. "I don't think that releasing the report at this time is necessary. The mere fact that someone has leaked out part of the report does not justify releasing all of it."

In other matters, Girolami told lawyers for 22 reporters that a state law does not protect calls and conversations they placed to Scott Peterson. Authorities wiretapped Peterson's phone before his arrest and alerted journalists last month that they had been taped.

Scott Peterson, 30, was arrested April 18. His wife, who was eight months pregnant, vanished Dec. 23 or 24 from her Modesto home.

Peterson could be executed if convicted; he has pleaded not guilty and is being held without bail at a Stanislaus County jail.

The sensational case has drawn widespread national media coverage. Hoping to preserve the possibility of seating an impartial jury, Girolami had raised the idea of a gag order.

Harris suggested imposing a limited order allowing attorneys to correct erroneous information while refraining from divulging case specifics. Geragos said that preventing lawyers from talking to reporters "isn't going to solve anything."

The case returns to court June 26 when the defense will ask Girolami to sanction prosecutors for what lawyers say was the unlawful taping of conversations with their client.

Deputy district attorney John Goold, a spokesman for the District Attorney's Office, has maintained that investigators did nothing wrong.