From what they have both said, he fathered both of those children with Jaycee [Dugard]," El Dorado County Undersheriff Fred Kollar told reporters.
The girls, now 11 and 15, had been living with their mother, now 29, in a series of sheds behind Garrido's house in Antioch, California, until they were discovered on Wednesday, Kollar said.
"None of the children had ever gone to school, they had never been to a doctor, they were kept in complete isolation in this compound, if you will, at the rear of the house," he said. "They were born there."
In a rambling telephone interview from jail, Garrido told CNN affiliate KCRA of Sacramento he was relieved at being caught.
"I feel much better now," he said. "This is a process that needed to take place."
Kollar said Garrido's wife, Nancy, was with her husband when Dugard was abducted from the street in front of her house in South Lake Tahoe. Dugard was already a registered sex offender at the time