It’s hard to see her in the crowd of men. She is the tiny figure towards the back.

The soldiers have ordered the men to strip to their underwear. Even some of the elderly ones. They gaze up at whoever is taking the photograph. It is almost certainly an Israeli soldier.

The image appears to have first been published on the Telegram account of a journalist with strong sources in the Israel Defence Forces.

The men look abject, fearful and exhausted. The little girl, who was noticed in the picture by a BBC producer, is looking away. Maybe something out of sight of the camera has caught her attention. Or maybe she just doesn’t want to look at the soldiers and their guns.

The military have told the people to stop here. Bomb-blasted buildings stretch off into the distance behind them. They are checking the men, for weapons, documents, any sign they might be linked to Hamas.

So often the suffering of this war is found in the detail of individual lives. The child’s presence, her expression as she looks away, is a detail that poses so many questions.

Foremost, who was she? What happened to her? The photo was taken a week ago.

A week of hundreds killed, many wounded, and thousands uprooted from their homes. Children died under the rubble of air strikes or because there wasn’t the medicine or medical staff to treat them.

Working with BBC Arabic Gaza Today programme we began searching for the child. Israel does not allow the BBC or other international media access to Gaza to report independently, so the BBC depends on a trusted network of freelance journalists. Our colleagues approached their contacts with aid agencies in the north, showing the photograph in places where the displaced had fled.

Within 48 hours word came back. The message on the phone read: “We have found her!”

Julia Abu Warda, aged three, was alive. When our journalist reached the family in Gaza City – where many from Jabalia have fled – Julia was with her father, grandfather and mother.

She was watching a cartoon of animated chickens singing, difficult to hear because of the ominous whine of an Israeli drone overhead.

Julia was surprised to suddenly be the focus of a stranger’s attention.

“Who are you?” her father asked, playfully.

“Jooliaa” she replied, stretching the word for emphasis.

Julia was physically unscathed. Dressed in a jumper and jeans, her hair in buns held by bright blue floral bands. But her expression was wary.

Then Mohammed began to tell the story behind the photograph.

Five times the family was displaced in the last 21 days. Each time they were running from air strikes and gunfire.

On the day the photo was taken they heard an Israeli drone broadcasting a warning to evacuate.

This was in the Al-Khalufa district where the IDF was advancing against Hamas.

“There was random shellfire. We went toward the centre of Jabalia refugee camp, on the road to the checkpoint.”

The family carried their clothes, some cans of tinned food, and a few personal possessions.

At first everybody was together. Julia’s dad, her mother Amal, her 15-month-old brother Hamza, a grandfather, two uncles and a cousin.

But in the chaos, Mohammed and Julia were separated from the others.

“I got separated from her mother due to the crowd and all the belongings we were carrying. She was able to leave, and I stayed in place,” Mohammed said.

Father and daughter eventually moved on with the flow of people heading out. The streets reeked of death. “We saw destruction and bodies scattered on the ground,” Mohammed said. There was no way to stop Julia seeing at least some of it. After more than a year of war, children have become familiar with the sight of those who have died violent deaths.

The group reached an Israeli checkpoint.

“There were soldiers on the tanks and soldiers on the ground. They approached the people and started firing above their heads. People were pushing against each other during the shooting.”

The men were ordered to strip to their underwear. This is routine procedure as the IDF searches for concealed weapons or suicide bombers. Mohammed says they were held at the checkpoint for six to seven hours. In the photograph Julia appears calm. But her father recalled her distress afterwards.

“She started screaming and told me she wanted her mother.”

The family was reunited. The displaced are packed into small areas. Bonds of family are tight. Word travels fast in Gaza City when kin arrive from Jabalia. Julia was comforted by the people who loved her. There were sweets and potato chips, a treat that had been stored away.

Then Mohammed disclosed to our colleague the deep trauma Julia had suffered, before that day of their flight from Jabalia to Gaza City. She had a favourite cousin. His name was Yahya and he was seven years old. They used to play together in the street. About two weeks ago Yahya was in the street when the Israelis launched a drone strike. The child was killed.

“Life used to be normal. She would run and play,” he said. “But now, whenever there’s shelling, she points and says, ‘plane!’ While we are trapped she looks up and points towards the drone flying over us.”

According to Unicef – the United Nations children’s agency -14,000 children have been reportedly killed in the war.

“Day after day children are paying the price for a war they did not start,” said Unicef spokesman, Jonathan Crickx.

“Most of the children I have met have lost a loved one in often terrible circumstances.”

The UN estimates that nearly all children in the Gaza Strip – nearly one million – need mental health support.

It is hard to call a child like Julia lucky. When you think of what she has seen and lost and where she is trapped. Who knows what will return in dreams and memories in the days ahead. By now she knows that life can end with terrible suddenness.

Her good fortune is in the family that will do whatever is humanly possible – in the face of air strikes, gun battles, hunger and disease – to protect her.

With additional reporting by Haneen Abdeen, Alice Doyard, Moose Campbell and Rudabah Abbass.