By Lauren Victory

CHICAGO (CBS) — Police are investigating an assault outside Boeing headquarters that left a woman with broken teeth and no pants.

The call initially came in as a sexual assault, after a passerby found the bruised and battered woman with no pants around 5 a.m. Sunday.

Investigators later determined the 49-year-old woman had not been raped.

Instead, four women had followed the victim after she left a nearby home in the West Loop, and struck her repeatedly. Before attackers ran off, they stripped the victim of her pants; leaving her cut and bruised. The woman also lost some teeth in the beating.

Police said the victim lost some personal property in the attack, but it was unclear if the attackers actually robbed her of anything.

Investigators were trying to determine if the assault was recorded on any surveillance cameras at Boeing headquarters or other nearby buildings.

It was unclear if the victim has any connection to Boeing.

No one was in custody Monday morning. Area Central detectives were investigating.