A frosty reception from Bishop Eamon Casey and his then comparatively affluent circumstances in Galway prompted the 1992 call to The Irish Times which disclosed that he had a son.
In 1991, when Peter was 16, he, his mother Annie Murphy and her then partner Arthur Pennell moved from the US to Kinsale, Co Cork.
"We originally thought we were going to move to Scotland, " Peter said in a recent interview with The Irish Times. "He was from Edinburgh. It was the early Nineties.They got the idea then, 'let's try Ireland'. Next thing you know we bought a house in Kinsale."
He added: “My stepfather, I guess, unbeknownst to me, drove up to Galway. He went down there and said [to Bishop Casey] ‘listen, your son really wants to meet you. Obviously you don’t have to admit who he is. Say he’s whatever’.
“I guess he had some choice words for Arthur which Arthur didn’t like very much. Arthur was not a man you did that to. He then returned from his trip and that was his new goal.
“My stepfather was a poor man that grew up poor in Scotland. He had this chip on his shoulder. There were the have-nots and the haves. That was it.
“He met Eamon, saw what he had and said ‘you’re a goddam have and I’m a have-not. You just slapped my face. Guess what . . .’ And that was it. You couldn’t talk him out of it.”
In February 1992 Pennell contacted The Irish Times. "I just didn't pay attention to it because this was my last semester. I was waiting to find out if I was accepted at UConn [University of Connecticut]. In my mind there were more important things to worry about.
"Finally one day my Mom goes 'there's a reporter coming over tomorrow and he's from The Irish Times and he's going to ask questions . . . just tell him the truth, tell him what you know'." The reporter was then Irish Times Washington correspondent, Conor O'Clery.
Arthur Pennell and Annie Murphy separated in 2001 and he died in 2006 at the age of 84.
An interview with Peter Murphy by Donal MacIntyre will feature in Print and Be Damned, a new series on the printed press in Ireland which begins on TV3 at 9pm on Thursday.