(CBS) — A 25-year-old woman fell to her death on Lower Wacker Drive in the Lakeshore East area early Sunday morning.

CBS 2’s Jeremy Ross reports police are describing it as a terrible accident.

The woman was leaning over the railing on Upper Wacker and fell to Lower Wacker, police said. She was pronounced dead on the scene.

The woman has been identified as Generra Lee, a mother of three children. A friend of Lee’s said she was on a party bus prior to the fall.

A man familiar with the area believes about four stories separate Upper Wacker from the ground below.

Police are calling it a death investigation.