Sinn Féin's Arthur Morgan has denied any Republican involvement in the killing of Joseph Rafferty in Dublin in April 2005.
He also stated categorically that Sinn Féin had nothing to hide in relation to the killing.
Esther Uzell, sister of the late Mr Rafferty, has announced her intention to run as an Independent candidate for the Dublin South East constituency.
She said she had reluctantly put her name forward for the election.
Ms Uzell said she wanted to highlight the alleged failure of Sinn Féin to fully co-operate with the investigation into the murder of her brother.
She added that she particularly wanted to highlight the alleged failure of the party's candidate in Dublin South East, Councillor Daithí Doolan, to co-operate with that investigation.
The 28-year-old courier was shot dead while he tried to start the engine of his van outside his apartment in west Dublin. He left behind a young daughter.
Ms Uzell claims that her brother was shot in cold blood by a member of the IRA, and that she has received no help from Sinn Féin which she accuses of helping to cover up the murder.
