Teens charged with fatal shooting of Chicago police officer during crime spree.

Four teenagers have been charged with first-degree murder in the fatal shooting of off-duty Chicago police officer Aréanah Preston. The suspects were allegedly on a robbery spree when they came across Preston and shot her. One of the suspects bragged about the killing in a phone call, which helped authorities crack the case. The suspects have all been previously convicted of robbery as juveniles. Preston's gun was taken in the shooting and has not been recovered.