The 911 dispatcher accused of mishandling a call from the cell phone of UW-Madison student Brittany Zimmermann the day of her slaying on Wednesday denied hanging up on the call, union officials said.

Shannon Maier, president of AFSCME Local 720, which represents Dane County courthouse and 911 center employees, said the dispatcher, who hasn't been named, contradicts center director Joe Norwick, who last week said the dispatcher ended the call from the slain student's cell phone.

"The dispatcher has indicated to us that she absolutely did not hang up," Maier said. "The disconnect happened on the other end."

Another union leader, Local 720 chief steward Laurie Lane, told reporters from WISC-TV and WKOW-TV earlier Wednesday that she'd heard a recording of the approximately 90-second call and all she could hear was faint background noise like a soft rustling. Police have said there was "evidence" in the phone call that should have prompted the dispatcher to send police but have not said what can be heard.

Paul Logan, a Dane County 911 center dispatcher and state president for the Association of Public-Safety Communications Officials, said he's listened to the call. While he wouldn't comment specifically on the content, he did say it's not unusual for authorities to differ on what they hear based on the context.

"Now that people are expecting to hear something, they're going to hear it," Logan said.

Dane County Executive Kathleen Falk's chief of staff Topf Wells said Lane was instructed Wednesday afternoon not to talk any more about the duration or content of the tape, which Madison police requested because it involves an ongoing investigation.

"We viewed (violating the police request) as a serious matter," Wells said.

Otherwise, he said, 911 center employees haven't been gagged or forbidden from talking to the press.

Maier said the dispatcher's handling of the call followed the 911 center's protocol, which says a cell-phone hang-up shall be called back "as time permits."

"Unfortunately she had two hang-ups in a row and a (third) call waiting," Maier said. "We don't believe she violated protocol."

The 911 center policy also says "waiting 911 calls shall be answered prior to calling back previous hang-ups or abandoned calls."

"Do they attempt to call back all 911 hang-ups?" Maier said. "Of course. But the protocol states 'if time permits.' As a union, we felt very strongly we needed to step up and defend her. We wanted her to understand her union is behind her."

Maier said the dispatcher asked for a transfer out of the 911 center weeks before the April 2 incident because of the hardship of long hours and mandatory overtime, among other things.

"Her partner is going to be retiring next year and she is looking for a more normal life, a Monday-through-Friday job, no weekends, no holidays," Maier said.

"At this point in her life she was looking at what her opportunities were to transfer to another county job. It was nothing related to the 911 center other than the hours and the amount of overtime they can be ordered to do."

State Journal reporter Chris Rickert contributed to this report.

Contact Patricia Simms at psimms@madison com or 608-252-6492, and Matthew DeFour at mdefour@madison.com or 608-252-6144