LONDON — Some of the girls had barely reached puberty. Many had come with parents in tow. At least one was only 8 years old.

It is not clear whether the bomber who killed 22 Ariana Grande fans, wounded 59 and incited a mass panic at her concert in the Manchester Arena on Monday night (May 22) knew that his homemade device would explode among victims who were young and included many girls.

But the traumatising effects put the attack in the same category as the Beslan school siege in Russia, the Peshawar school massacre in Pakistan and the mass kidnapping of schoolgirls in Chibok, Nigeria: It grabbed the adult world’s attention in ways that some indiscriminate attacks do not.

“It’s intended to shock,” said Mr William McCants, a senior fellow at the Centre for Middle East Policy at the Brookings Institution and an authority on the Islamic State, which claimed responsibility for the Manchester assault. “You get maximum fear by attacking a vulnerable population: kids.”

Mr McCants, the author of the 2015 book The ISIS Apocalypse: The History, Strategy and Doomsday Vision of the Islamic State, said that “the thing with ISIS is, it doesn’t worry about offending mass public opinion”.

By Tuesday evening, the police in Manchester had publicly identified only a few of the dead. The details that were emerging about the victims reinforced what Mr McCants and others described as the shock value craved by plotters of such attacks.

Saffie Rose Roussos, 8, the youngest of the confirmed dead, was described by her school principal, Mr Chris Upton, as a “beautiful little girl” who was “quiet and unassuming, with a creative flair”.

Saffie, from Lancashire in north-western England, attended the concert with her mother and older sister. News reports said both had been hospitalised for injuries.

“The thought that anyone could go out to a concert and not come home is heartbreaking,” Mr Upton said.

The first victim to be publicly identified was Georgina Bethany Callander, an 18-year-old health and social care student known for her big smile and love of pop music.

Callander’s Instagram account showed a young and joyful woman who appeared to adore animals and Disney films. She had also posted a photograph of her driver’s licence, which she received in December 2016. News reports said she had died with her mother at her side. Old photographs on social media showed her wearing glasses and braces.

She was a student at Runshaw College in Leyland, Lancashire, where administrators expressed “enormous sadness” and said they would offer counselling to students.

Callander was a fan of the bands Fifth Harmony and One Direction. On her Instagram account, she named Beauty and the Beast and Captain America as her favourite films, and Wicked as her favourite musical.

Her social media accounts show a young and idealistic woman who had criticised a dog meat festival in Yulin, China, and supported the Women’s March on London in January.

The Manchester Evening News identified another victim, John Atkinson, 26, from Radcliffe, a town in the Manchester area. A fundraising page was established for his funeral.

A fourth victim was identified late Tuesday as Kelly Brewster, 32, from Sheffield, an avid concertgoer who had attended the show with her sister, Claire Booth, 34, and Booth’s 11-year-old daughter, Hollie.

Relatives said Brewster died trying to shield them from the blast. Hollie’s legs were broken, her mother’s jaw was broken, and both suffered wounds from shrapnel, including embedded bolts in their bodies, The Guardian reported.

Mr Payton Williams, one of Brewster’s friends, who confirmed she had died, said she was “very smart, funny lady with a heart of gold”.

As the authorities scrambled to identify the dead and as relatives scoured local hospitals for their loved ones, one mother clasped a framed photograph of her young daughter and made a tearful appeal on BBC television for any information about her, saying she was worried sick. Dozens of others posted photographs of the missing on social media, asking for information about relatives and friends.

Some Polish citizens were among the missing, said Mr Jakub Krupa, the British correspondent of the Polish Press Agency, citing the Polish Ministry of Foreign Affairs.

Ms Grande, 23, a US singer, attracts legions of young female fans to her concerts, chaperoned by parents. She has also broadened her fan base by promoting lesbian and gay rights and celebrating diversity — concepts that are antithetical to the Islamic State and similar jihadi extremist groups.

While it is possible that Ms Grande’s particular audience may have been deliberately targeted, some terrorism experts said it was the size and youth of the audience and the vulnerability of the event that had enticed a group like the Islamic State.

“It was particularly attention-grabbing,” said Professor Brian Nussbaum, a professor at the College of Emergency Preparedness, Homeland Security and Cybersecurity at the University of Albany. “ISIS is more interested in violence for violence’s sake and the momentum that comes with that.”

Others said the predominant gender of Ms Grande’s audience may have been directly relevant for the attack plotters.

“These are young girls, they haven’t started their lives, so everybody’s sitting in their homes and saying ‘my God, they went to have fun and look what they got’,” said Professor Wagdy Loza, a psychiatry professor at Queen’s University in Ontario and former chairman of the Extremism/Terrorism section of the Canadian Psychological Association.

“The psychological impact is much, much more than killing a bunch of people in an office or workers in their 50s,” he said. “It does make more impact when you see children.” NEW YORK TIMES