Police in Seattle are investigating a mass shooting near the city's iconic Space Needle on July 26 that left two people dead and five others injured, including a toddler.

Around 6 p.m. Sunday, a volley of gunfire sent thousands of people running from a festival at Seattle Center.

The ghost gun, a Polymer80 9-mm handgun with an extended magazine, was taken from a 15-year-old boy when he was arrested at the scene, Seattle police Chief Shon Barnes said at a news conference Tuesda...