The gunman shot himself on a West Seattle sidewalk several hours later as police closed in on his location.
The woman was shot in a parking lot near Town Hall at Eighth and Seneca Streets around 11:30 a.m. Wednesday, police said. The woman was rushed to Harborview Medical Center where she later died.
A witness told officers the gunman and woman were in an argument, then the man pulled out a gun and shot the woman in the head.
"I see this guy leaning down over this woman kicking her, then he shot her in the face," one witness said.
The man then jumped into an SUV and drove away.
The car was recovered about a half hour later in the 4100 block of Delridge Way in West Seattle, and officers spotted a gun in side the car. Officers canvassed the neighborhood, searching homes for the gunman.
Around 4 p.m., plainclothes officers saw a man on the street near 37th Avenue SW and SW Raymond Street that matched the description of the gunman in the cafe shootings. As officers closed in on the man's location, the man got down on his knees and shot himself in the head, police said.
Originally police said the man had died, but later a Harborview Medical Center spokesperson said the man was still alive, but in critical condition.
The shooting near Downtown came about 30 minutes after a mass shooting that left three dead and two critically wounded at a cafe in the University District.
Investigators said the witnesses' description of the shooter at Eighth and Seneca matched the description of the shooter at Cafe Racer.
The woman has not been identified. Police say they don't believe the shooter knew the victim.