A massive barn fire that killed more than a dozen horses this week was an accident, investigators said Friday.
An exact cause remains unknown.
"We have speculation that it could have been a [charcoal] grill, and there is speculation there was an outside controlled burn in the area, but we can't confirm either one of those 100 percent ... so we will not make a declaration that either one of them was the cause," Tony Huemann, chief of the McHenry Township Fire Department, told The Northwest Herald.
Wednesday's blaze destroyed the barn at M&R Overlook Farms.
County health department spokeswoman Debra Quackenbush said the final number of horses confirmed dead is 18. Twenty-two other horses were saved and are in good health.