Two men were killed at a coffeehouse in the city's University District, while a woman died in the carjacking, Seattle police said. Three more people -- another two men and a woman -- were wounded at the coffeehouse.
Investigators were looking for any connections between the two incidents, which happened about four miles and a few minutes apart, police spokesmen said.
Suspect shot and killed himself (above picture of suspect in cafe)
"We're definitely in a dynamic situation right now," Deputy Police Chief Nick Metz told reporters.
The gunman ran away from the coffeehouse shooting.
"Whether he is armed at this time, we don't know," Metz said. But he added, "We're assuming he's very dangerous."
One of the wounded had life-threatening injuries, while the other two were seriously hurt, the department said. The black sport-utility vehicle was found empty a few miles southwest of downtown, police reported.