Authorities in Colorado released the names of the six people killed during a weekend birthday party when a gunman who was angry about not being invited opened fire before taking his own life. 

The Colorado Springs Police Department identified the victims as Melvin Perez, 30, his wife, Mayra Ibarra De Perez, 33, his mother, Joana Cruz, 52, and his brother, 21-year-old Jose Gutierrez. Mayra's siblings were also killed: Sandra Ibarra-Perez, 28, and 26-year-old Jose Ibarra.

The suspect, identified as Teodoro Macias, 28, had dated Sandra Ibarra Perez for a year and had a history of controlling and jealous behavior, including trying to isolate her from her family, authorities said. 

"At the core of this horrendous act is domestic violence," Police Chief Vince Niski said. "The suspect... displayed power and control issues in this relationship. When he wasn't invited to a family gathering, the suspect responded by opening fire and killing six victims."

The six victims who were killed during a birthday party in Colorado Springs, Colo., were identified Tuesday as Jose Gutierrez, Sandra Ibarra, Melvin Perez, Joanna Cruz, Mayra Perez and Jose Ibarra. (Facebook)

Macias did not have a criminal history and there were no reports of domestic violence between him and Ibarra-Perez, authorities said. No protection orders were in place at the time of the shooting, police said. 

The party was at Joana Cruz's house in the Canterbury Mobile Home Park as two families gathered to celebrate a birthday. The families were connected through the marriage of Melvin Perez and Mayra Perez, who were present with their children. 

The shooting occurred just after midnight Sunday. 

Macias walked into the home, where seven adults and three children -- ages 2, 5 and 11 -- were inside and shot the six victims in "quick succession" before killing himself, said police Lt. Joe Frabbiele. The children have been staying with relatives, police said. 

The children were near where the shooting took place but were found unharmed.

Officers found a Smith & Wesson semi-automatic 9mm. handgun near Macias along with two 15-round magazines, one of which was empty, police said. Police recovered 17 spent shell casings at the scene.

A memorial is seen on Monday outside a mobile home in Colorado Springs, Colo., where a shooting at a party took place a day earlier that killed six people before the gunman took his own life. (AP Photo/Thomas Peipert)

Authorities were not sure how Macias came to possess the weapon. The firearm was purchased by someone in 2014 from a local gun store, Frabbiele said. 

"The suspect did not purchase the firearm during that transaction," he said. "This is the only listed transaction for this firearm. We're still investigating how and when the suspect came to possess the handgun."

The gun was not reported stolen and the serial was not damaged, he added. 

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Authorities received three 911 calls shortly after the shooting. In one call, rapid gunfire was heard. One adult was able to escape the shooting and called 911 to report that someone had shot his family. 

Three other family members -- all teenagers -- left the home shortly before the shooting to retrieve something from a neighbor. They returned before police arrived and attempted to render aid and console the children, police said. 

Officials urged the public to take domestic violence seriously. 

"In Colorado, we’ve had domestic terrorism incidents where lots of people were killed, we’ve had random acts like going into a King Soopers or a movie theater, but let’s not forget about the lethality of domestic violence," Colorado Springs Mayor John Suthers said.

He was referring to the March mass shooting at a King Soopers grocery store in Boulder that left 10 people dead and the 2012 Aurora mass shooting at a movie theater.