A fire in rooftop garden of a high-rise building sent a plume of white smoke billowing over part of downtown Seattle Monday night. Firefighters were called to the scene just before 7:30 p.m. of the 17th floor of the Russell Investment Center located at 2nd Ave. and University, next to the Seattle Art Museum. Crews were able to quickly extinguish the flames and keep the fire from spreading to another building. Investigators said it started in the rooftop garden, then ignited a tree and nearby grass.