IOWA CITY, Iowa (AP) -

Investigators are using dogs to search for a missing 15-year-old Iowa girl in hog confinement buildings linked to the man suspected of kidnapping her.

Special agent Bill Kietzman of the Iowa Division of Criminal Investigation said Tuesday that 20 law enforcement officials with dogs were searching for Kathlynn Shepard at hog lots where Michael Klunder worked.

Kietzman said many of the areas have already been searched multiple times, but that investigators were using "different dogs to see if we have any luck."

Police say Klunder abducted Kathlynn and a 12-year-old friend last week while they were walking home from school in Dayton. The 12-year-old escaped at a hog confinement where Shepard took them, but Kathlynn has been missing. Police say Klunder committed suicide hours after the abduction.