Prosecutors said they planned on charging Peterson with double homicide for the deaths of Laci and the infant son. ``He'll be charged with capital murder,'' with the option of seeking the death penalty, said Stanislaus County District Attorney Jim Brazelton. ``There are no other suspects in this case.''
Peterson, 30, was arrested by plainclothes police in San Diego before noon Friday. The arrest was made hours before the results of DNA tests on the bodies were known because Peterson was considered a flight risk, and had indicated that he had discovered he was under police surveillance, California Attorney General Bill Lockyer said.
Modesto police and state agents used wire taps on phones and radio transponders on vehicles to keep track of Peterson's whereabouts in the San Diego area, where his parents live, Lockyer said. Authorities obtained an arrest warrant Thursday, and feared Peterson might flee to Mexico, said Modesto Police Chief Roy Wasden.
He wouldn't discuss possible motives for the alleged murder.
Peterson was being driven to the Stanislaus County jail in Northern California on Friday night for a court appearance next week. His attorney, Kirk McAllister, did not immediately return telephone messages Friday from The Associated Press.
The arrests came nearly a week after the badly decomposed bodies of Laci Peterson, and her son were found within a mile of each other - about three miles from where Scott Peterson said he went fishing the day his wife disappeared.
The bodies were identified Friday evening through a comparison with DNA samples from Scott Peterson and Laci Peterson's parents.
``We're scientifically convinced the match is one in billions,'' Lockyer said.
A spokeswoman for Laci Peterson's family said relatives were devastated by the confirmation of the deaths, but grateful they finally had an answer after months of uncertainty.
``Families in their circumstances will always tell you the worst thing is not knowing,'' said spokeswoman Kim Petersen, executive director of the Carole Sund-Carrington Memorial Reward Foundation. ``I don't know if relief is the right word. ... The waiting this week has been horrific for them.''
Friday's announcements drew a crowd of well-wishers to the Peterson's home. Many brought flowers, some stood silent while others said quiet prayers. They remembered Laci Peterson as a bright, friendly person.
``My heart goes out to the family,'' said Shanti Cardey, 29, outside the house with her two young girls. ``I feel a lot of sadness and anger. I feel very sorry for the family, I pray for them everyday.''
Raynette Poe, 36, said she was angry: ``How can he hurt his own child and why? My heart goes out to Laci's family.''
From virtually the moment his wife was reported missing, Scott Peterson's moves and statements have been scrutinized by authorities.
Modesto police seized his boat, pickup truck and nearly 100 items from the couple's house but had not formally named him as a suspect in his wife's disappearance.
Peterson traded in his wife's Land Rover for a new pickup truck, considered selling their home and eventually admitted an extramarital affair with a massage therapist while his wife was pregnant with the couple's baby.
Shortly after, Peterson said he'd told his wife about the affair in the days before she vanished.
``It (the affair) was not a positive, obviously ... but it was not something that we weren't dealing with,'' he told ABC's ``Good Morning America.'' ``It wasn't anything that would break us apart.''
The affair turned Laci Peterson's family against the son-in-law they had earlier supported. They begged him to cooperate with Modesto police, who had labeled him ``uncooperative.''
Scott Peterson launched his own search effort, separate from the one organized by his wife's family and sanctioned by police. At one point, as searchers looked in the San Francisco Bay and around Modesto, Scott Peterson showed up in Los Angeles to distribute fliers to volunteers at a local hotel.
``We simply have to expand the geographical area,'' he said at the time.
In February, Scott Peterson told MSNBC he missed his wife and the child she was to bear.
``I can't drive. I can't sleep,'' he said then. ``Sometimes I feel I just can't do it. I feel like I'm in a dark corner and I just can't function.''