Other local police agencies were called in to help control the crowds.
It stems from the death of Kenneka Jenkins, whose body was found in the Crowne Plaza Hotel freezer earlier this month.
WATCH: HOTEL VIDEOS OF KENNEKA JENKINS
Surveillance video from inside the hotel shows Jenkins staggering through the hallways into the kitchen area.
The protesters started in front of the hotel and marched to the police station after one person was arrested.
Rosemont police said a person was arrested for threatening to kill a police officer. Charges against the person are pending, police said.