A Chicago police officer was unintentionally shot and killed by her partner after they chased a suspect into an apartment and encountered another person with a rifle, officials said. Krystal Rivera, 36,

Adrian Rucker, 25, of Freeport, Illinois, is facing multiple felonies, including armed violence, possession of a fraudulent ID, and possession of a firearm without a FOID card.

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.