WILLIAMSON COUNTY, Ill. – A man killed his estranged wife before taking his own life Friday in southern Illinois.

The Williamson County Sheriff’s Office is investigating the case as a murder-suicide. Investigators say Robert Aumilller, 36, and Michelle Aumiller, 32, died in the incident.

Just before 9 a.m. Friday, deputies responded to an active shooter report at 310 West Plaza Drive in Carterville, Illinois, about two hours southeast of St. Louis.

Within minutes, deputies arrived to the scene and found Michelle suffered from gunshot wounds. She was rushed to a hospital, but later died from her injuries.

The sheriff’s office used a lockdown for nearby schools in Williamson and Johnson counties while police attempted to look for the gunman. Police later found Robert’s vehicle in a field in Cambria, Illinois. Authorities found Robert dead from a self-inflicted gunshot wound.

Investigators say Robert and Michelle were still married, but considered estranged at the time of the incident. The Williamson County Sheriff’s Office is leading the investigation.