BEAVER FALLS — Authorities are trying to determine who has set fire to at least 13 abandoned homes or other buildings in Beaver Falls.

The fires began in late August and all targeted abandoned homes with no utility service or garages.

Residents are concerned the fires are the work of a serial arsonist, but investigators say they can’t know that until they trace the origin of each fire. The latest fires occurred about 9:45 p.m. Saturday at an abandoned home and two more abandoned buildings burned Sunday night.

Beaver Falls Fire Chief Mike Stowe said nobody has been hurt in the fires. That’s partly because the buildings were known to be abandoned.