Chicago police officials say an officer killed this week was accidentally shot and killed by her partner after they encountered someone with a rifle when they chased a suspect into an apartment.

Officer Krystal Rivera was excited to celebrate her daughter's 11th birthday this weekend. But Rivera's life was tragically cut short late Thursday, when she was fatally shot in the back by a bullet fired by another officer.

Krystal Rivera, the Chicago police officer shot and killed in Chatham, was a loving mother, friend, and devoted police officer who cared deeply about protecting the community.