McGuinness negotiated alongside Gerry Adams with the Secretary of State for Northern Ireland, Willie Whitelaw, in 1972. In 1973, he was convicted by the Republic of Ireland's Special Criminal Court, after being arrested near a car containing of explosives and nearly 5,000 rounds of ammunition. He refused to recognise the court, and was sentenced to six months' imprisonment. In court, he declared his membership of the Provisional IRA without equivocation: "We have fought against the killing of our people... I am a member of Óglaigh na hÉireann and very, very proud of it".