A mother shot her two sons, then set her house on fire Friday before turning the gun on herself in west suburban Elmhurst, police say.

Jamie Jones, 43, shot her sons Jason Harris, 16, and Nathan Harris, 19, about 9:30 p.m. in the 3N300 block of Willow Road, the DuPage County sheriff’s office said. She proceeded to set her house on fire, then fatally shot herself.

The three bodies had already been removed from the building by the Elmhurst Fire Department by the time the DuPage County sheriff’s deputies arrived, the sheriff’s office said.

What initially began as a fire investigation was later ruled a murder-suicide, the sheriff’s office said.

“An act like this is completely inconceivable,” DuPage County Sheriff James Mendrick said. “This will be a trying time for the family, the and our first responders who dealt with the aftermath of this horrible incident. We offer sincere condolences for anyone affected, and urge anyone who is going through stressful times in their lives to please seek help.”

The deaths are being investigated by the DuPage County coroner’s office along with the DuPage County sheriff’s office and the DuPage County state’s attorney’s office, the DuPage County Government said in a statement.

The Suicide Prevention Lifeline operates a 24/7 hotline for people who may be in distress or know someone who is. They can be reached at 1-800-273-8255.