Hazmat crews evacuated people who live near Kern Park area Sunday afternoon.
The Milwaukee Fire Department said neighbors called them about a van that they thought had something suspicious inside. Officers arrested a person accused of possession of narcotics.
"I saw a young man being pulled off, being arrested, being put into the back seat of a police car and driven away," said John Hughes, who lives in the area.
Firefighters said they did not find anything "overly hazardous."