WINONA (AP) -  Authorities investigating last week's fire that devastated an older section of downtown Winona have ruled nothing in or out.

Spokesman Doug Neville of the Minnesota Department of Public Safety says the investigation is expected to take a while.

Friday's fire destroyed three building, including the Islamic Center of Winona. No one was hurt.

Deputy Winona Police Chief Tom Williams says fire investigators over the weekend finished cleaning by hand as much as they could of the rubble inside the back corner of the Islamic center, where they believe the fire originated.