The Taoiseach has challenged the Sinn Féin leader to explain where he got the names of party members connected to a longstanding murder case.

It's after Gerry Adams named four party colleagues in an email to the Garda Commissioner, over the murder of prison officer Brian Stack in 1983.

Adams says he got the names from Brian Stack's son Austin - who denies ever passing them on to the Sinn Féin leader.

In the Dail, Fianna Fáil's Micheal Martin said the dispute raises questions about where Adams obtained the names that he passed on: