A shop owner has been jailed for at least 27 years for the murder of 15-year-old customer Paige Doherty in his back office. John Leathem, 32, stabbed the teenager more than 60 times when she stopped at his Delicious Deli in Clydebank, West Dunbartonshire, on 19 March and dumped her body in bushes two days later.

The married father of two was sentenced at the high court in Glasgow to life with a minimum term of 27 years on Thursday after pleading guilty to her murder at an earlier hearing.

The south court was packed with Paige’s family and friends for the sentencing. There were shouts of “scum” and “monster” as Leathem was led away to the cells.

In passing sentence, Judge Lady Rae said the attack was “savage and frenzied”, and described the killing as “truly reprehensible and impossible to comprehend”.

Leathem, a first-time offender, attacked Paige in the back office of the Delicious Deli shortly after 8.20am, apparently after a short exchange about a job.

A postmortem found Paige suffered 61 stab wounds, mainly to her head and neck, and 85 further cuts thought to have been sustained as she tried to fight off her attacker.

Leathem was captured on CCTV carrying her body out of the shop in a bin bag and putting it in the boot of his car. Footage also shows him leaving his shop to buy anti-bacterial wipes, bin bags and bleach.

He is understood to have stored Paige’s body in a shed at his nearby home over the weekend before driving to a wooded area off the A82 on the morning of Monday 21 March and dumping her body, which was discovered by a member of the public.

At the previous hearing, Rae told him: “This was a savage, frenzied attack on a child.”

Leathem’s lawyer, Ian Duguid QC, said the murder was a “spontaneous, gross overreaction”.

He said Leathem claimed to have taken Paige into the back office to discuss a job application, where he says he told her he would have to speak to her mother due to her age and that there were other candidates for the position as a shop assistant.

Leathem claims Paige responded: “I thought I was getting a job,” before adding: “I’ll just say you touched me,” the court heard.

Duguid said reports showed his client had no anger management issues and was a “quite unexceptional individual”.

He referred to his earlier statement during Leathem’s plea that a conversation about a job led to him being “frightened” at a perceived threat from Paige that she would say he “touched her inappropriately” if he did not give her a job.

Duguid said: “That is no excuse for the way he behaved. It’s inexplicable. This is an individual who is acting so out of character. There is no explanation that can be found.”

Rae referred to Leathem’s claims during her sentencing. She said: “You claim … she threatened to reveal you had touched her inappropriately if you didn’t give her that job. No evidence has been placed before me to support this. Even if true, your reaction was in no way mitigating of this appalling, wicked crime. There is no evidence or motive to explain the ferocity of this attack.”

“It is impossible to comprehend how an apparently happily married man, with a young child, who is running a successful business, is capable of such a horrific level of violence.”

Paige was described by her grandmother as a “kind and selfless person and all-round good girl”. Her family have said they will never get over what happened to the teenager.

The court heard that her mother, Pamela Munro, hears her daughter’s screams in her nightmares and her stepfather, Andrew, said the family could not get out of their heads “the terror that she must have experienced”.