SAN FRANCISCO (AP) — An FBI agent who spent 18 years on the Jaycee Lee Dugard case says the Antioch couple charged in her 1991 abduction were never considered suspects.

Special Agent Chris Campion said the bureau exhausted thousands of leads about Dugard’s whereabouts, sometimes with the help of confidential informants and court-ordered wiretaps.

Yet Campion said in the interview posted on the FBI Web site Friday that Phillip and Nancy Garrido ‘‘just did not come up on the radar screen.’’

The Garridos have pleaded not guilty to kidnapping Dugard and holding her captive in their backyard.

Cadaver dogs returned to the property Monday to search for possible links to other open cases.