Emanuel Asks For Hate Crime Investigation Into Racial Slurs Heard On Police Radio Frequencies

CHICAGO (CBS) -- Mayor Rahm Emanuel has sent a letter to Cook County State's Attorney Anita Alvarez and U.S. Attorney Zachary Fardon asking them to open a hate crime investigation into racial slurs broadcast on Chicago Police frequencies.

Investigators say that the transmissions are being made by a private citizen or citizens with non-city issued equipment.

"The language used and the racial intolerance expressed do not represent the values of our police department or our city," Emanuel wrote. "We are at our best when we hold ourselves to the highest standards."

The first incident occurred on March 13 when a conversation between police officers and dispatchers at a 911 call center was interrupted by an unknown individual who repeatedly used racial slurs. There have been at least three subsequent incidents.