The Brief Three people were killed and four others were injured during a shooting at Seattle Center on Sunday evening. The American flag on top of Seattle's Space Needle is flying at half-staff Monday morning following Sunday's deadly shooting at Seattle Center. Seattle City Center shooting suspectsWhat we know:Police believe at least two people were shooting at each other. FOX 13 Seattle reached out to the Space Needle to ask why the American flag was flying at half staff, and they confirmed it was in response to Sunday's deadly shooting at Seattle Center. The Source: Information in this story comes from the Seattle Police Department, Space Needle and original reporting by FOX 13 Seattle.