MADISON, Wis. (AP) -- Dane County's top official says a better response to a 911 call from a college student before she was murdered still could not have saved her life.

County Executive Kathleen Falk apologized at a news conference for numerous errors employees made responding to the April 2 call from Brittany Zimmermann's cell phone.

But she says she does not believe the University of Wisconsin-Madison student's murder could have been prevented.

Falk says a county dispatcher inquired three times about whether an emergency existed but heard nothing before the call ended. She then failed to call the number back as required under department policy.

Falk says the call does contain sounds that have significance but they were not heard by the dispatcher.