Negotiations with a person barricaded inside of an apartment Saturday morning prompted some people to be evacuated from nearby units.
The standoff has since ended, and the suspect has surrendered.
Thornton Police say they first arrived at the apartment complex at 1882 E. 104th Ave. at around 3:15 a.m. after someone called and said they heard a gunshot.
No one was injured, police say, and no one was in the apartment with the suspect.
No major roads closed due to the standoff.
The suspect has not been identified.