This happened while they were walking near clashes between supporters and opponents of deposed Islamist President Mohamed Mursi.
As Egypt votes this week on a successor to Mursi, Samir's loved ones now want authorities to declare the boy a "martyr", a term used to portray as heroes members of the security forces killed in fighting with Islamists.
They do not want Samir to have died in vain, just another bystander killed in the political struggle which erupted after then army chief Abdel Fattah al-Sisi removed the Muslim Brotherhood's Mursi from power last July.
"The most important thing we ask from the state, or from Sisi personally, is that Samir is like any soldier, like any officer or policeman," said his father Ahmed, who works for the Suez Governorate.
"They have to honour him like they honoured the others."
If Sisi wins the presidential election as expected, he will be the latest military man to rule the biggest Arab nation.
He is seen as a strong figure who can end the political and economic instability that has dogged Egypt since a popular uprising ousted President Hosni Mubarak in 2011.
Under Sisi's watch, security forces have killed hundreds of Muslim Brotherhood members and arrested thousands, driving the group underground and easing political tensions.
But for families like the Gamals, full confidence in leaders can only come once the government helps them come to terms with their loss.
Clinging to the memory of their son, they insist the government only passed a law severely restricting protests because of Samir's death, though there is no evidence of that.
REMINDERS OF TRAGEDY
Pictures of Samir identified as a "martyr" hang all around the house. Samir's family have even named a street outside their home after him. It says "The Martyr Samir al-Gamal".
The family lives in a dusty central quarter of Suez, a hotbed of the 2011 revolt against Mubarak.
After Samir's death, the Governor of Suez visited the family home. Part of it is collapsed, the walls are mouldy and paint is chipped. He promised to move them to a new location, the family said.
The family has only officially presented the authorities with one request since Samir's death: a job for his brother.
"A simple thing. In an oil company perhaps, as a normal employee. We didn't ask for him to become an engineer or a doctor or a government job," said an uncle, also named Samir.
Samir's mother, Afafa Abdel Magid, 49, blames Mursi supporters for his death.
"I saw who killed my son. A guy wrapped up in black outfit with a ribbon worn by Islamists," she said. "I can't tell you how horrible it was."
So far 12 people have been arrested in the case but not sentenced, in sharp contrast with the over 600 Muslim Brotherhood members recently condemned to death in the biggest mass trials in Egypt's modern history.
"They shouldn't wait all this time. Why are they waiting?" said Samir's father Ahmed.