MADISON (WSAU) Brittany Zimmermann's family is hoping somebody will come forward with information about her murder. The Zimmermann family has placed ads on a Madison billboard and inside buses.

Zimmermann was a student at the University of Wisconsin-Madison when she was killed in her apartment in 2008. Today would have been Zimmermann's 23rd birthday.

Madison police have never publicly identified a suspect in the stabbing.

The stabbing was the subject of a lawsuit over a mishandled 9-1-1 phone call. Zimmerman was able to call from her cellphone, but the call was treated as a hang-up by Dane County dispatches. Information about the call was never forwarded to Madison police.