"My thoughts go out to the Diers family," said the mayor. "He will be missed."
A few minutes later, a second statement from City Hall said Diers is "alive and well."
The seattlepi.com reports the mayor had confused Diers with Joe Dear, a former chief of staff to Gov. Gary Locke and director of the Washington State Investment Board. Dear died of cancer this week at the age of 62.
Diers himself appeared not to be too disturbed that the mayor's initial statement was wrong. Tweeting to friends, he wrote: "Thanks everyone for your concern, but I don't really have time for death."
It was the second gaffe by the mayor's office in the past week. The first was the botched disciplining of a Seattle police officer by Interim Seattle Police Chief Harry Bailey.