Melted siding is seen Tuesday on one of two four-story buildings under construction at Mount Auburn Apartments at 138 Mount Auburn Ave. in Auburn. The damage is the result on an adjacent apartment building, also under construction, that burned to the ground late Sunday night. The cause is under investigation. Russ Dillingham/Sun Journal

Charred debris lies Tuesday where a four-story apartment building went up in flames late Sunday night at Mount Auburn Apartments, 138 Mount Auburn Ave. in Auburn. Excavators knocked down what was left of the building, one of two under construction. Shannon Moss, Maine Public Safety spokesperson, said the Office of the State Fire Marshal has been working on the investigation since Sunday to determine the cause. Russ Dillingham/Sun Journal