RAPID CITY, S.D. (AP) — A group of landowners is suing a South Dakota utility and a Minnesota-based telephone company for alleged negligence in the third-largest wildfire in the Black Hills region's history.

The Rapid City Journal reports that the lawsuit was filed Friday in Custer County against Black Hills Power and Hanson Communications. Landowners allege the companies failed to use proper care around the root system of a large tree in Custer State Park.

Investigators say December's Legion Lake fire began when a tree fell onto a power line in the park. Flames spread into Wind Cave National Park and onto private property, ultimately scorching 84 square miles.

The lawsuit seeks unspecified damages.

A spokeswoman for Black Hills Corporation, the parent company of Black Hills Power, declined to comment on the lawsuit.

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