Authorities on Monday are investigating the motive behind a deadly Colorado birthday party shooting that left six people dead and the suspected gunman, who killed himself, police said. Authorities found six adults dead and one man seriously injured early Sunday in Colorado Springs. The injured man later died at the hospital, the Colorado Springs Police Department said. The suspected shooter was the boyfriend of a female victim at the party at a mobile home park attended by friends, family and children. Ref. USAToday.