Northern Ireland's chief of police says the Irish Republican Army is responsible for last month's massive bank robbery in Belfast.

Chief Constable Hugh Orde said Friday that investigative efforts have implicated the IRA, but he declined to disclose details of the specific evidence leading to this conclusion.

The criminals got away with $42 million.  In response, Northern Bank announced Friday that it will remove its currency from circulation and replace it with new bank notes.  The change will make the money stolen on December 20 illegal tender.

The IRA and its political wing, Sinn Fein, have repeatedly rejected accusations of involvement in the bank robbery.

Friday's announcement further strains attempts to revive a suspended 1998 power-sharing agreement between Sinn Fein and Protestant parties that favor continued union with Britain.  IRA disarmament has been a key sticking point.

Some information for this story provided by AFP and Reuters.