Sunday morning, first responders were notified of a two-vehicle accident with injuries at Cottonwood Road and Southport Road (Route 8).
The second vehicle was unoccupied, and was parked on the side of the road.
A male driver and female passenger were reportedly discovered unresponsive, still in the vehicle.
The male was flown by Life Flight helicopter to OSF Healthcare Saint Francis Medical Center in critical condition. His name and condition are unknown.
The female passenger, 25-year-old Michelle Siegel of Edwards, was found dead in the passenger seat of the vehicle.
Autopsy results showed Siegel had suffered head and neck trauma from the accident, and likely died instantly.
This story will be updated.