The Aurora Fire Department review, along with incident reports of the July 20 shooting at a screening of the film "Dark Knight Rises," were obtained through an open records request, The Denver Post reported Wednesday.
Ambulances that arrived at the scene of the shootings were blocked behind parked cars, police vehicles and 1,400 fleeing moviegoers.
When emergency medical workers arrived, fire dispatch directed them to a staging area to await instructions.
Aurora Deputy Fire Chief Danny Wilcox said first responders didn't hear the cry for people needed at the rear of the theater.
Why that information wasn't relayed to paramedics more quickly is unclear, the Post reported.
The city declined to comment on the reports, citing a court-issued gag order.
Questions concerning the dispatch are the latest raised about the July shooting that killed 12 people and wounded 58 others.
James Eagan Holmes, 25, arrested shortly after the incident, is being held without bond after entering a plea of innocent.