Police are searching for a suspect accused of shooting and killing four adults in the early hours of Sunday morning at a home in Aurora, Colorado. 

Joseph Castorena, a 21-year-old man who police say "has a history involving domestic violence," was still on the run as of Sunday afternoon. 

His partner, an adult female, and two "very young children" were found alive at the home unharmed. Three adult males and one female were found dead. 

Police were originally called to the home in the Aurora neighborhood of Delmar Parkway about suspicious activity around 2:06 a.m. The dispatcher heard gunshots during that phone call a few minutes later and police arrived at 2:15 a.m. 

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Castorena, who is 5'4" with a slim build and has a lion tattoo on his neck, lives a couple of blocks away from the crime scene with his family, police said. 

"Earlier this week, a restraining order had been issued directing the suspect not to go to the residence or come near the domestic partner," Aurora Police Chief Dan Oates told reporters near the scene on Sunday. "This was an accumulation of events here that led to this."

Castorena and his partner have children, but they are out-of-state and safe, Oates said. 

Police are using drones to search the neighborhood for Castorena, who is considered armed and dangerous.