Police soon learned the man they had shot actually lived in the home, and that he had just shot the intruder in the bathroom moments before. He was taken to a local hospital, where he was pronounced dead.
When police pulled up to the house, officers heard gunshots coming from inside and rushed in, where they saw a man with a gun.
Police have not yet released the identity of either the homeowner or the intruder.
The officer, whose name also has not been released, was placed on administrative leave as per department policy when an officer fires their weapon on duty.
Authorities tell KDVR they also found a juvenile inside the home who was seriously injured by the intruder.
Aurora police received multiple calls about a break-in at the suburban Denver home at about 1.30am on Monday.
"This is a very heartbreaking and tragic situation for everyone involved". That juvenile was taken to the hospital after receiving injuries from that intruder.
A family member identified the man as Richard Black, an Army veteran.
'He was a family man - a grandpa that was protecting his family.
Police in Colorado fatally shot a man in his home after mistaking him for a burglar. Because this incident occurred within Adams County, the facts of the investigation will be presented to the Office of the District Attorney for a determination of whether criminal charges should be filed against any involved person. "We are providing assistance through our victim advocates to help the family of the deceased resident through this very hard time". According to police, officers then encountered an armed man and an officer shot him.
The police department voice mail ends with an appeal: "Thank you for calling the city of Aurora, the safest large city in Colorado".
Aurora Police Chief Nicholas Metz has disclosed some limited information in connection with the incident.