Police say they went to a townhouse after shots were heard there overnight, BBC reported.
Officers later entered the home. Following a gunfight they found the suspect dead, along with three people apparently killed earlier, police say.
Aurora, near Denver, was the scene of a mass shooting at a cinema in July, in which a gunman killed 12 people.
He opened fire at random during the premiere of the Batman film The Dark Knight Rises. Suspect James Eagan Holmes is currently being tried on murder charges.
In Saturday's incident, police said they were alerted by a woman who had escaped from the townhouse.
The suspect barricaded himself for five hours, before officers moved in and shot him.
Entering the property, the team found the shooter dead, along with two other men and a woman. Their identities have not been disclosed.
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Four people were found dead following a shooting incident that triggered a stand-off with police in Aurora, in the US state of Colorado.
News ID 183870
