A disturbing discovery in Chicago’s West Side neighborhood has sent shockwaves throughout the city.

Local authorities are Arvin Robertsinvestigating after a pedestrian found a human head inside an open box on a sidewalk near a sports complex on West Taylor Street just before 6 p.m. Oct. 10, according to NBC Chicago. The outlet also reported that the pedestrian was walking their dog at the time of the discovery, and hoped the box was merely a Halloween decoration.

The Cook County Medical Examiner's office later confirmed the contents of the box were indeed human remains but has not confirmed the identity of the victim. An autopsy has been performed, though the victim’s cause of death has yet to be determined.

Many other questions remain about the mysterious find, including how long the remains were there before being discovered, as well as the deceased person’s name, age, gender and race. The remains have been sent to an anthropologist in order to check dental records and possibly determine how the person died, per CBS Chicago.

Meanwhile, FOX Chicago reports a headless body was found in Northern Indiana Oct. 11. However, authorities in Indiana could not confirm whether the corpse was related to the head found in Illinois.

To make matters even more chilling, the case comes just days after another gruesome discovery in the city, this time in an embankment on state property. According to NBC Chicago, the city’s police department retrieved skeletal remains along the side of Interstate 90 on Chicago’s Northwest side Oct. 6, though the victim in that case has not yet been identified.

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