DENVER (AP) — As the horror unfolded for police first on the scene of the Colorado theater massacre, the officers repeatedly sent out urgent pleas for more ambulances even as a two-man crew and their rig were idling just a few miles away.

Radio traffic from last Friday’s shooting in Aurora, Colo., showed emergency personnel struggling to grasp both the scope of the tragedy and mobilize a response.

While some ambulances were quickly called to duty, it took dispatchers more than 20 minutes into the crisis to ask the Cunningham Fire Protection District and other nearby agencies to provide aid at the multiplex in suburban Denver.