SEATTLE (Reuters) - An incumbent Democratic state representative in Washington was headed for a decisive re-election victory on Wednesday even though he died last week, results indicate.

Roger Freeman, a first-term representative from Federal Way, a city between Seattle and Tacoma, had 53 percent of the vote, compared to 46.9 percent for his Republican challenger, Jack Dovey.

Freeman, 48, died last week after a battle with cancer. His death came after ballots were mailed to Washington voters, where all voting is done by mail.

"This is extremely rare," said Brian Zylstra, a spokesman for the secretary of state's office. "But there are protocols in place."

Once all ballots are finalized in coming weeks, if Freeman wins the vote, Democrats still will hold on to his seat in the state House of Representatives, Zylstra said.

Democrats in Freeman's district, which spans two counties, will select three names for a temporary replacement and the King and Pierce County councils will vote to appoint one of those candidates to the seat for one year, according to state election rules.

The seat would be on the ballot in 2015 to fill out the remainder of the two-year term, the rules say.

Should the Republican candidate win, he will take the seat in Olympia at the start of the next legislative session.

(Reporting by Victoria Cavaliere; Editing by Bill Trott)