Imposing the minimum life tariff on 52-year-old Samuel Dunwoody at Belfast Crown Court, Judge Corinne Philpott QC told the killer he had "taken advantage" of the kindness shown to him by Margaret Telford.
At the end of his trial last June, Dunwoody, originally from Belfast but now with an address at High Tower in Birmingham, was unanimously convicted of murdering 68-year-old Mrs Telford in February 1988.
Dunwoody remained impassive in the dock as Deputy Recorder Judge Philpott condemned him to a sentence which will mean he will be over 70 before parole commissioners can even consider releasing him.
The jury heard that having confronted Dunwoody when he tried to steal money from her, he beat her about the head and neck before strangling Mrs Telford, also known as Peggy, in her Twaddell Avenue home in the north of the city and then fled.
The killer was on home leave from prison at the time and speaking outside court shortly after Deputy Recorder Judge Philpott had delivered her damning sentence, Detective Chief Inspector Peter Montgomery described how Dunwoody had left his prison cell, killed the pensioner and then went back to prison.
At the time of her death she was a widow, living alone and in poor health. However Samuel Dunwoody decided to exploit that by murdering a much loved mother, friend and neighbour.
DCI Peter Montgomery
Dunwoody had a string of violent convictions for assault causing actual bodily harm and battery, including attacking the same woman three times between 1982 and 2009.
During his trial the killer refused to take the witness box to refute the Crown evidence against him.
On Friday prosecuting QC Ciaran Murphy said the murder was aggravated by reason of the fact that Peggy had been vulnerable, Dunwoody had been trying to steal from her and that he was a dangerous offender who had shown "capacity for extreme violence".
He told the court the pensioner's murder had understandably had a "devastating effect" on her family. Defence QC Terence McDonald submitted that alcoholic Dunwoody had not intended to kill his victim and that he had a "dysfunctional background".
Judge Philpott however disagreed with the lawyer and told the court she was of the view that Dunwoody did indeed intend to kill.
She said although Peggy was kind to Dunwoody and his family, whom he knew through working at a welfare advice centre, even "providing clothes to his children...you shortened her life".
The judge recounted that having called at the pensioner's home, Dunwoody "made an excuse to go upstairs, clearly looking for money" but Peggy realised something was wrong.
When she went to contact the authorities, Judge Philpott said Dunwoody was scared his prison licence would be revoked so strangled her.
Jailing Dunwoody for life with a minimum tariff of 19 years, the judge told him: "You have lived in the community as a freeman for 25 years and in my view, you took advantage of a 68-year-old woman who showed you kindness."
Following the sentencing, DCI Montgomery said his first thoughts were with Peggy's friends and family who had lived for 25 years with the crime unsolved.
"The Telford family have endured unnecessary suffering over the past 25 years. I'd like to put on record my thanks to Peggy's son Peter and daughter Victoria, who has since passed away. I hope today's events will provide some comfort and closure to them," he said.
He said that but for Dunwoody, Peggy "would have lived in the safety and sanctuary of her home".
DCI Montgomery added: "Today justice has been served for Peggy and serves as a reminder that although a large passage of time has elapsed police will regularly review cases and where there are new opportunities presented we will pursue them vigorously."
Peggy's son Peter also spoke outside the court, saying that for the family the intervening years had been "like holding your breath" but that the sentencing on Friday was like "a breath of fresh air".
Murder victim Margaret Telford pictured below.