MANKATO, Minn. (AP) - A woman credited with potentially averting a school attack in the southern Minnesota city of Waseca says the suspect acted strangely as he approached a self-storage facility near her apartment.

Chelsoe Schellhas says she watched him cut though her back yard to reach the facility. She says he slogged through calf-deep puddles instead of taking a parallel path on the dry road. She watched him struggle for about 10 minutes to unlock a unit before finally sliding open the door, stepping inside and closing it. She had her cousin call police.

Court documents say police found the 17-year-old working with bomb-making material by the light of a single lamp. He told police he was planning to kill his family and attack Waseca Junior-Senior High School.