Police Say Boyfriend Responsible for Shooting at Colorado Birthday Party

More than half of mass shootings in recent years involve a perpetrator who killed an intimate partner or family member, including the gunman who killed six people in Colorado Springs.

COLORADO SPRINGS — In the early hours of Sunday, the sound of the television inside Gerardo Torres’s mobile home in Colorado Springs was overwhelmed by gunfire outside. Then, a woman’s cry from a gray mobile home across the narrow lane from his: “No! No!” As Mr. Torres called 911 and stepped out to investigate, he heard more shooting, then silence. He grimly told the 911 dispatcher that he believed everyone inside was dead.