MADISON, Wis. -- The union that represents a former Dane County 911 dispatcher accused of mishandling an emergency call from a slain University of Wisconsin-Madison student shortly before she was killed will appeal her three-day suspension.

AFSCME Local 40 representative Larry Rodenstein said that he just filed a grievance to the discipline, which was handed out Dec. 18 -- about eight months after county officials said Rita Gahagan mishandled the April 2 call that came from Brittany Zimmermann's cell phone. The call disconnected after one minute.

"The union believes that the county was unable to establish just cause (for the suspension)," Rodenstein said.

He said that the union is contesting the discipline on the basis it believes there is "not sufficient cause" for the county to take such an action.

Dane County Executive Kathleen Falk earlier said that the suspension was appropriate and that Gahagan, who now works in another county job, was being disciplined for failing to call back Zimmermann after the call disconnected. Officials said that Gahagan proceeded to move onto another 911 call and never told police or called back Zimmermann's number, which officials said violates protocol.

Union officials have said in the past that they and Gahagan also couldn't hear -- as county officials and police have asserted -- "sounds of an emergency." Authorities haven't released many details about what sound might be audible on the call citing the ongoing investigation into who killed Zimmermann.

Rodenstein said that if Gahagan made any errors, she deserved to receive only a reprimand of some kind under the progressive discipline policies of the county.

Gahagan now works in county child support, which is a transfer she requested. If she were suspended, she would get three days off without pay.

Controversy over the call Zimmermann apparently made before she was killed has lingered for months. Police weren't sent to the scene until about 40 minutes after the call when Zimmermann's fiancé found her dead and called 911.

Stay tuned to WISC-TV and Channel 3000 for continuing coverage.