A lawsuit claims the 2017 Legion Lake Fire, that started in Custer State Park and scorched more than 55,000 acres was caused by the negligence of Black Hills Power and a Minnesota telephone company. Seven landowners filed the lawsuit Friday in Custer County against Black Hills Power and Hanson Communications. The suit claims the companies caused the December fire because they improperly cared for the roots of a large tree in the park that fell onto a power line. The suit alleges that “the root system was cut when a utility trench was dug adjacent to the tree, causing the tree’s soil root plate to be severely damaged, rendering it vulnerable to toppling.” Fire investigators determined that a falling tree started the fire when it hit a power line. The suit seeks damages to be determined by a jury.