The father of an Omagh bomb victim has asked Gerry Adams if he will change his stance on asking people to come forward with information about the atrocity.
Victor Barker, with other Omagh bomb relatives
Victor Barker accused the Sinn Fein leader of hypocrisy over his appeal for people to give evidence about the murder of Belfast man Robert McCartney.
Mr Barker's 12-year-old son James was one of 29 people killed in the 1998 Real IRA bomb attack.
He said he originally asked Mr Adams to make an appeal five years ago.
Mr Barker said the Sinn Fein leader replied that he could not do so because the RUC was an "unacceptable police force".
Recently, Mr Adams appealed for anyone who has any information about the the murder of Mr McCartney to come forward.
Mr McCartney, 33, was stabbed to death outside a Belfast bar in January.
"I've since written to him again last week and asked him in view of his decision in relation to the McCartney case whether he would also be prepared to change his stance over the Omagh bomb," Mr Barker said.
"It seems to me to be hypocrisy to encourage people to come and give evidence in one case but not in the other."