CAMBRIDGE (AP) — Authorities plan to continue searching a rural area in Isanti County through this week as part of their investigation into the 1989 disappearance of a Maple Grove teenager.

Amy Sue Pagnac was 13 when she disappeared 25 years ago. Her case got renewed attention last month when police searched her parents' Maple Grove home.

On Monday, authorities searched west of Stanchfield in Isanti County. Police say the search will continue 24 hours a day through Friday.

Pagnac disappeared Aug. 5, 1989. Her mother's husband, Marshall Midden, told police he and Amy had been tending crops on the family's Isanti County farm when he stopped at an Osseo gas station. He told police he used the bathroom, and when he came out, Amy was gone.