At least five people were killed and 18 others injured in a mass shooting at a nightclub Saturday in Colorado Springs, Colorado, according to police.

Authorities received numerous 911 calls beginning at 11:57 p.m. and responded to the scene at the Q Club, Colorado Springs Police Lt. Pamela Castro said. “They located an individual inside who we believe is the suspect,” Castro said. "At this time, the suspect is being treated, but he is in...