COLORADO SPRINGS, Colo. (AP) — A gunman who killed six people at a Colorado birthday party held by his girlfriend’s family over the weekend opened fire because he had not been invited and then killed himself, police said Tuesday.

The shooter had been in a relationship with one of the victims for about a year and had history of controlling and jealous behavior, Colorado Springs police Lt. Joe Frabelle said at a news conference. Police said the gunman had no reported incidents of domestic violence during the relationship and didn’t have a criminal history. No protective orders were in place.

Frabelle identified the gunman as 28-year-old Teodoro Macias and the other victims as members of his girlfriend’s extended family.

Investigators don’t know yet how the suspect obtained the weapon, which Labelle described as a Smith & Wesson handgun. He said it was originally purchased by someone else in 2014 at local gun store but was not reported stolen. The suspect had two 15-round magazines, one of which was empty, and police recovered 17 spent shells at the scene.

The shooting occurred at a home at the Canterbury Mobile Home Park on the east side of Colorado’s second-largest city.

Outside the modest home this week, a small crowd of mourners paid their respects, leaving bouquets of yellow roses and devotional candles on a small table. They hugged each other and left without comment under a dark, gray sky. Someone closed a partially open window in the home from the outside.

Neighbor Gladis Bustos tearfully recalled the home’s owner, whom she identified as Joana, as a warmhearted, hardworking person who always took the time to say hello to her neighbors, ask how they were doing, and brag about her children.

“She was an incredibly pleasant woman, very beautiful, happy all the time,” Bustos said. “She loved to chat. And she was very proud of her family.”

“We’re all in shock,” Bustos added. “How can this happen here? This is all so painful, so devastating, so overwhelming.”

The first fire crews to respond to the shooting were told to stay back because of possible gunfire — then given an all-clear to approach the home an agonizing eight minutes after the initial dispatch, according to a recording of a Colorado Springs dispatch call.

More than eight minutes in, the dispatcher tells first responders at one point that “police on scene are advising that there are four victims and that you are clear to go in.” Minutes later, the dispatcher says: “The sergeant on the scene is saying that medical is cleared to enter for all six patients. … They’re saying we have six.”

The attack follows a series of mass shootings — defined as four or more dead, not including the shooter — to plague the U.S. this year, including one on March 22 at a crowded supermarket in Boulder, Colorado, that killed 10 people, including a police officer.

Before the Colorado Springs shooting, a database compiled by The Associated Press, USA Today and Northeastern University showed there had been at least 11 mass shootings since Jan. 1, compared to just two public mass shootings in 2020.

Colorado Springs saw a 2015 attack on a Planned Parenthood clinic that killed three people, including a police officer, and injured eight others. In 2007, a man killed two people and wounded three at Colorado Springs’ New Life Church before taking his own life. Earlier the same day, he’d killed two people and injured two at a Youth With a Mission Center in the Denver suburb of Arvada.

After the Boulder shooting, Colorado lawmakers introduced a bill to create a state “Office of Gun Violence Prevention” to educate residents about gun safety and collect data on Colorado gun violence. Other bills advancing through the Democrat-led Legislature would tighten background checks, allow municipalities greater freedom to adopt their own gun control laws that are stricter than state law, and require a person facing a protection order related to alleged domestic violence to report what firearms they possess.

Associated Press writers James Anderson and Colleen Slevin in Denver contributed to this report.