Officers first responded to reports of an intoxicated man pointing a gun at people and drivers in the 2700 block of 1st Avenue South late Monday night.
They say the man, later identified as 36-year-old Andrew J. Law, refused commands to drop his weapon. Police say he then pointed the gun at them, forcing an officer to open fire.
Law was killed, and police now say the gun he was holding was a replica.
At a Wednesday press conference, interim Police Chief Harry Bailey showed members of the media two guns -- one real and the other the fake that Law was holding.
"I can tell you right now that one is real and one is a replica, the question is whether you would want to take a chance, on this at night, with your life," he said.
Monday's incident was the second officer-involved shooting in as many days for Seattle police, following a Sunday morning shooting in Belltown.
The suspect in that shooting was carrying a real gun. That man is expected to survive.