Double jeopardy killer Dennis McGrory will serve minimum 25 years for murder and rape of Jacqueline Montgomery in 1975

Double jeopardy killer Dennis McGrory has been sentenced to life with a minimum term of 25 years for murdering and raping teenager Jacqueline Montgomery in 1975.

He was cleared of the crime nearly half a century ago but was found guilty following a second trial after new DNA evidence was found.

Now in his mid-seventies – and sentenced today to at least 25 years and 126 days – he is likely to die in jail.

McGrory, a violent drinker, was 28 when he raped and murdered the 15-year-old in her home in Islington, north London.

He was angry and looking for his estranged partner Josie, Jaqueline’s aunt. It was thought he attacked her to force her to reveal Josie’s new address.

Jacqueline’s father found his daughter’s body when he got home.

She had been raped, stabbed through the back, heart and diaphragm, and strangled – with the cord of an iron found around her neck.

McGrory carried out the attack “fuelled by alcohol and driven by rage and lust for Jackie”, said judge Mr Justice Bryan during sentencing today.

He said the killer had an “unreciprocated sexual interest” in Jaqueline and had “tried it on” with her before.

There was “very significant suffering before death” – with the judge calling it a “horrific, violent and sustained ordeal”.

Jacqueline would have been “terrified”, he added, with experts believing she could have survived with the horrific injuries for up to 10 minutes before she died.

“How any man could inflict such sexual and physical harm upon a 15-year-old child who had done them no harm beggars belief?” the judge said.

He said there was also the possibility she was tortured because of the iron cord around her neck and a burn mark on her leg.

‘A billion-to-one match’

McGrory was described in court as showing “not one iota of remorse or compassion” for his victim and her family.

He continued to deny the murder despite the damning new DNA evidence against him.

The killer originally claimed he had been attacked and beaten up by four strangers on the night of the murder and had not been to Jacqueline’s home.

But the prosecution said they were injuries caused when his victim tried to fight him off.

Eventually, a judge at the Old Bailey threw out the case in 1976 after deciding the prosecution evidence, which was purely circumstantial, was too weak.

But vaginal swabs from Jacqueline’s body had been kept and were retested using new scientific techniques.

They showed a billion-to-one match with McGrory’s DNA, his unique genetic fingerprint. He was re-arrested and charged with rape and murder for a second time.

It took jurors at Huntingdon Crown Court just three hours to find him guilty of rape and murder.

This was a rare retrial – and the oldest – after the scrapping of the ancient double jeopardy legal principle which prevented a defendant being charged with the same crime twice.

The law was changed in 2003 to allow retrials of acquitted defendants if new and compelling evidence emerged and the Director of Public Prosecutions (DPP) was convinced that each case was fair and in the public interest.

Since the change in the double jeopardy law there have been only a few retrials of previously acquitted defendants.

The most famous is the successful prosecution of Gary Dobson who had been found not guilty over the murder of black teenager Stephen Lawrence in South London in 1993.

He and another original suspect David Norris, who hadn’t previously stood trial, were convicted in 2012 and jailed for life.