Richmond, Calif. ? The investigation into two bodies found in San Francisco Bay is focused on determining whether they were Laci Peterson and the baby she was carrying, a state criminalist said Wednesday.

The state crime lab is comparing DNA from Peterson and her parents with tissue and bone taken from the decomposed bodies of a woman and infant boy found this week a mile apart on the rocky shoreline east of San Francisco.

“We don’t have another person in mind,” said lab supervisor John Tonkyn.

The 27-year-old substitute teacher vanished on Christmas Eve from her home in Modesto, 90 miles southeast of Richmond. Her husband, Scott Peterson, said he saw her as he left to go fishing that morning in Berkeley, not far from where the bodies were found.

The lab was analyzing cheek swabs taken from the missing woman’s parents and hair from her hairbrush. Those findings will be compared with DNA from the bodies that were found. The child’s body still had the umbilical cord attached.

Asked why investigators weren’t using dental records, Tonkyn said the lab wasn’t provided with teeth from the Contra Costa County Coroner’s office. “Sometimes not a full skeleton has been found,” Tonkyn said.

According to published reports, the mostly skeletal adult body was clad in maternity undergarments, without a head and missing parts of the limbs.

Laci Peterson’s family members remained sequestered in Modesto on Wednesday. “There’s no news, we’re just waiting,” stepfather Ron Grantski said. “Until they confirm there really isn’t anything.”

Scott Peterson, 30, a salesman, hasn’t surfaced publicly since the bodies were discovered Sunday and Monday. While his in-laws stood by him early in the investigation, a rift developed after he acknowledged having an affair with a Fresno woman while married.

Scott Peterson has not been named as a suspect, but police have seized his boat, truck and items from his house.