Michigan law enforcement authorities are investigating a suspicious barn fire near Grand Rapids that claimed the lives of 13 therapy horses.

A statement from the Kent County, Michigan, Sheriff’s Department, said firefighters from the Lowell Fire Department responded to a call about a fire at The Barn for Equine Learning on April 8. The facility provides equine-assisted learning and therapy for young people, and riding lessons for the community at large.

Upon arrival, firefighters found the structure fully engulfed in flames. All 13 horses in the barn at the time of the fire died, the statement said.

The property owners notified fire officials at the scene about several inconsistencies with the condition of the barn and surrounding property. The Lowell Fire Department subsequently contacted the Kent County Sheriff’s Department, the statement said