Seamus Kearney from Gorteade Road in Swatragh will be sentenced on Friday for the IRA murder of Constable John Proctor on 14 September 1981.
The RUC reservist had been visiting his wife June McMullin and their newborn baby son at the Mid Ulster Hospital in Magherafelt when he was gunned down.
Recounting the events of that day, June said: "There were big plans to get home, we had just moved into a new home and the plans were being made. There was big excitement.
"A few of us in the ward had sandwiches and tea, a picnic as such, and when it was time to go I left Jonny down the corridor and said goodnight to him. As he came to the front of the hospital I waved at him then he went round the corner and I heard the gunfire."
Even though the Troubles were at their height, this murder shocked Northern Ireland when it emerged John Proctor had just left his wife and child when he was attacked.
It was like a nightmare, it was like something you didn't dream of, you just though 'God how can this be happening to me?'
June said the next few days passed in a blur of pain and grief - the funeral, hundreds of messages of sympathy, and the realisation that at the age of 22 she had lost her childhood sweetheart and had a two-year-old son and a newborn baby to bring up.
He was now named Jonny in honour of his father.
June said: "The family rallied around and his family were great, and there was always great support, but when it came to late at night and everybody went home, you would turn the key in the door and go up the stairs and that was you, on your own. That was the loneliest time."
Four years ago John Proctor's mother contacted the Historical Enquiries Team and the case was re-opened.
Forensic tests - not available in 1981 - on a cigarette butt found at the scene which had been sealed in an evidence bag 29 years earlier matched the DNA profile of Seamus Kearney.
He had already been jailed for attempting to murder UDR soldiers in 1984. Last month the 54-year-old, who lived not far from John Proctor, stood trial in Belfast Crown Court.
Ms McMullin said: "To sit in the court room and look at him, to think - you ruined a family, you took a life. How could you do that? For what?"
Outside the court, June proclaimed "our day has come" after the Diplock judge pronounced Kearney guilty 32 years after her husband's murder.
To think - you were 25 when you did that and Jonny was 25 when you took his life.
She added: "It was like a weight had been lifted off my shoulders - finally we got justice."
In recent weeks the comments from the Attorney General John Larkin that there should be an end to prosecutions has for offences committed before the Good Friday Agreement in 1998 have angered June and her family, who are so relieved that justice has finally been done.
"He was totally out of line to think people don't deserve a day in court," she said.
"Has he lost anyone? Has he been in a position anyone else has been in, has he an empty place at the table. No, I wouldn't think it."
Seamus Kearney, who lived a short distance away from John Proctor and his family, will be sentenced on Friday. Under the terms of the Agreement he may only serve two years in jail.
June said: "I would like it to be longer but we did sign up for the Good Friday and I really don't think people understood what it was all about at the time but we got him. We got guilty.
"He's a murderer and no matter how long he does he will always be classified as a murderer. With us getting a guilty verdict it's very important for other families to know that there is hope out there and maybe someday they'll get the chance to get into court as well."