Jonathan Dowdall claims Gerry Hutch told him he was one of the men who shot David Byrne during a boxing event at the Regency Hotel in Dublin in 2016.
The former Sinn Féin councillor has begun giving evidence against Mr. Hutch, who is on trial for Mr. Byrne's murder.
He told the judges that he was present when key cards to a room at the Regency Hotel were handed over to Mr. Hutch the night before the shooting.
He also claims he met with the accused a few days later.
He described him as being in a 'panic' and claims he told him he and another man shot Mr. Byrne.
Dowdall said Gerry Hutch arranged this meeting in a park in Dublin because he wanted to set up a meeting with his Republican contacts in Northern Ireland.
