Police suffered their highest casualty count in more than two years in the Colorado Springs Planned Parenthood shootings, a reflection of the danger officers face in mass shootings.

One officer was killed and five others were shot and wounded in the Nov. 27 attack.

A recording of police radio transmissions depicts a chaotic scene, with officers trying to find the gunman and save injured civilians while under deadly fire themselves.

Experts say that's typical in a mass shooting and makes things worse for officers. Some shooters don't care whether they live or die, and officers often confront the gunman without backup and without much information.

Pete Blair, a criminal justice professor at Texas State University, says police are wounded in about 25 percent of cases like the Colorado Springs shooting.