Chicago Police and the FBI are investigating if saboteurs placed bugs in a breakfast buffet prepared for delegates at the Democratic National Convention on Wednesday.

“Multiple unknown female offenders are alleged to have entered a building…and began placing unknown objects onto tables containing food,” the convention’s information center said in a statement. “The offenders are believed to have then left the area. One victim was treated and released on-scene. Along with CPD, FBI-Chicago is assisting in the investigation.”