A gunman opened fire during a birthday party in Colorado Springs early Sunday morning, leaving seven people dead, including the gunman, who shot his girlfriend and then himself.Authorities in Colorado said the suspect spared the children at the party, who were present inside the trailer at a mobile home park. The Colorado Springs Police Department said "the suspect, a boyfriend of one of the female victims, drove to the residence, walked inside and began shooting people at the party before taking his own life."A motive has yet to be determined. The massacre about 70 miles south of Denver is the latest in a resurgence of mass shootings in the United States, including one in Boulder, Colorado, where a man has been charged with 10 counts of murder after a shooting spree at a supermarket. Colorado is also the state where two other deadly rampages took place, both in the Denver area: the 1999 shooting at Columbine High School that killed 15 people including the two perpetrators, and the 2012 shooting in a movie theater that killed 12 people.Police said in a statement that they withheld releasing details of the shooting for several hours "in order to properly and respectfully notify family members of the deceased and ensure support was in place," adding that the names of the victims will be released later.