Dmitry Fotyanov was shot in Russia's Far Eastern town of Dalnegorsk by unidentified assailants driving past in a minibus. He died later from wounds in hospital, the Prosecutor General's office said in a statement.
Fotyanov, from the United Russia party which supports President Vladimir Putin, came second in the first round of voting on October 8 and was preparing for a tight race against his independent rival in the second round on Sunday.
The Prosecutor General's office said it was looking into whether the murder was connected with the elections. United Russia officials had no doubts.
"The only version for Dmitry Fotyanov's killing is a political murder carried out to get rid of an election candidate," senior United Russia parliamentary Vasily Usoltsev said in remarks posted on the party Web site www.edinros.ru
Usoltsev did not mention any suspects but said that Fotyanov confronted criminal groups and corrupt officials in Dalnegorsk.
Fotyanov will now be replaced by a local businessman who came third in the first round of the vote.

Copyright Reuters, 2006