LEA COUNTY - Investigators say they've figured out where the grassfire that burned 75-thousand acres near Hobbs started.
The Stiles Complex Fire began Friday afternoon as four separate blazes.
The State Forestry Division says those were caused either by motor vehicle emissions or a catalytic converter.
Strong winds fanned the flames into one big blaze that burned seven homes, two barns, and several other buildings before was contained sunday night.
Crews are continuing to patrol the area, and are watching over hay bales and a diesel tank still burning at a dairy farm.