Sergeant Dempsey started his law enforcement career with the Addison Police Department in 2003 working as a patrolman. He was assigned to the Investigations Section in 2006 as a Detective. In 2013, he was promoted to the rank of Sergeant.
Sergeant Dempsey received a Bachelor's degree in Accounting from Elmhurst College. He is trained as an Evidence Technician, Juvenile Officer and is a Certified Truck Enforcement Officer. He previously served as the Department's Asset Forfeiture Coordinator and was formerly a member of the DuPage County Major Crimes Task Force.
Sergeant Dempsey has received numerous awards and commendations during his time with the Addison Police Department while working in the Criminal Investigations Section.