That was Ross. He was assassinated by the IRA in 1975 by 2 Provo's who became known as the Balcombe St gang after the siege in which they were apprehended. McWhirter was targeted for offering a reward for their capture. They were in prison for 24 years until GFA in '99.
Bonus point if you can tell me who, in 1987, handed a petition to then-prime minister , Thatcher, demanding better visiting conditions for the murderer along with "the immediate transfer of Irish political prisoners to prisons near their homes"