(AP) — Authorities are scaling back their search for a missing Iowa teenager abducted from a rural school bus stop this week.

The state Department of Public Safety says trained law enforcement will narrow their search around Dayton on Saturday for 15-year-old Kathlynn Shepard.

Authorities say they’re focusing on terrain that’s difficult to navigate and requires specialized skills and equipment, so citizen volunteers are not needed. Residents are encouraged to check their rural properties for anything suspicious.

Police suspect Michael Klunder took Kathlynn and a 12-year-old girl on Monday to a hog confinement building several miles away. The younger girl managed to escape. Klunder was later found dead of self-inflicted injuries.

Authorities will search land between the hog confinement and a location where the girls’ backpacks were found.