Double jeopardy: The murder of Jacqueline Montgomery in 1975

The body of Jacqueline Montgomery, 15, was found when her father returned to the family home in Offord Road, Islington, in the early hours of 2 June 1975.

The teenager had been stabbed, beaten about the face and strangled with the flex of an iron. Her clothing had been partially removed, suggesting she had been sexually assaulted.

The room showed signs of a struggle and the phone had been left off the hook, possibly as Jackie attempted to call for help. The line had been engaged since the late morning of the previous day.

Detectives with the Metropolitan Police quickly focused on Jackie’s ‘uncle’ Dennis McGrory, who was then 28 and had a history of drinking and violence towards women. He had been the long-term partner of Jackie’s aunt until she left him and moved to Manchester to get away from his abusive behaviour.

Police believe that he attended Jackie’s home, near Highbury and Islington station, in the early hours of June 1 to look for her aunt.

McGrory had been drinking heavily in the N16 (Stoke Newington / Newington Green) area until around 4am and was later seen by a neighbour in an “excitable” state.

Visibly shaking, McGrory showed the neighbour a piece of paper with an address written on it, which he claimed had been been given to him by four men who assaulted him in the street.

Police were later able to show that the piece of paper was a page from Jackie’s diary which included the address of her aunt.

When McGrory was arrested, he had a bruised lip, a long scratch to his neck and smaller scratches to his wrist and arm – which he claimed were caused when he was assaulted by the “geezers”.

He was charged with murder on 10 July and went on trial the following year. However he was acquitted after the judge ruled there was insufficient evidence for a conviction and directed the jury to find him not guilty.

That verdict meant that he could not be tried again for the murder under the double jeopardy law that existed at the time.

The law was changed in 2003.

In November 2015, at the request of Jackie’s family, the Metropolitan Police began a review of the case and re-submitted a swab taken from the body in 1975.

That swab was found to contain a DNA profile which was matched to McGrory, who had been added to the database following an unrelated conviction in 2009.

The DNA match also provided evidence that McGrory had raped Jackie at the time of the murder.

It was enough to convince the Court of Appeal that the original verdict should be quashed.

McGrory was charged a second time after being arrested at his home in Milton Keynes in March 2020. He was first put on trial at the Old Bailey in March 2022, with prosecutors arguing he took his anger and frustration out on the victim when he could not track down her aunt. The trial also heard evidence that McGrory had made sexual comments to Jackie and had even threatened to rape her.

Although that trial was aborted when McGrory fell ill, he was convicted of rape and murder during a second trial at Huntingdon Crown Court on 19 December 2022.

Detective Constable Jane Mascall, from the Met’s Specialist Casework Team, said: “In 1975 there was no way of testing for DNA, so detectives had to rely on other forms of evidence. Samples from the time were carefully labelled and securely retained. And this is how they remained until all these years later when they were retrieved for further testing during a review of the case, as requested by Jackie’s sister.

“Forensic experts discovered a trace of McGrory’s DNA on a swab taken from Jackie which meant we were also able to establish that he had raped her, something officers at the time could not prove. This crucial piece of evidence has allowed us to apprehend this violent man who thought he had got away with murder. Kathy was determined that her sister’s case should not be forgotten and that determination has paid off.”

In January 2023, at the age of 75, McGrory was sentenced to life imprisonment with a minimum of 26 years before parole, meaning he will likely die in prison.

Jackie and I always said that we could trust no-one. A violent man who had been living within our family murdered my sister. He has been able to live his life. He has spent nearly fifty years as a free man doing as he pleased. I find that unbearable when my sister didn’t even reach her sixteenth birthday. His actions caused trauma to so many people and there were no consequences for him.

The investigation of the last few years has meant revisiting memories of the murder which has caused pain and stress for me and my family and I am relieved that we finally have justice for Jackie.

Jackie’s sister, Kathy, speaking in 2022

Detective Supterintendent Rebecca Reeves said: “McGrory is a violent man, a bully who terrified the women in his life. He thought he had got away with murder, but thanks to the hard work of specialist detectives and expert forensic scientists, he has now finally been held accountable for taking the life of a young girl in 1975.

“Jackie was courageous and bright. She stood up for her aunt who had fled from McGrory’s violence and abuse.”