On Monday, the Egyptian Interior Ministry identified the bomber as Hasan Rafat Ahmad Bashandi, 17, an engineering student at the Banha campus of al-Zaqaziq University and a resident of the relatively squalid northern Cairo district of Subra al-Khaima.
Several members of the Bashandi family had been rounded up over the weekend for DNA sampling analysis which eventually helped Egyptian investigative police identify the bomber's remains.
But neighbours and friends who knew Bashandi well are still grappling with the idea that the mild-mannered and generous young man could have taken his own life and in doing so killed three French tourists and an American and wounded several more.
They describe the Bashandi family as well-educated. Adel Bashandi, the eldest is a law graduate and works for a private sector company. Isam is an arts student while the youngest brother Ala is in the later stages of his engineering degree.
Helmi: Hasan Bashandi's mother
kept her children out of trouble
The youngest sister, Iffat, is 10-years-old and is in the fifth grade.
Neighbours say they never heard of trouble between the children.
Huda Helmi, daughter of the building owner, lives in the apartment across the hall from the Bashandis.
She remembers the Bashandi children as being particularly well-raised by their mother.
"Their mother took good care of her children to the extent that we wanted to nominate her for the Perfect Mother television programme," Helmi told Aljazeera.net.
"Whenever a fight happens on the street they don't even look from the balcony. She doesn't allow her children to get in contact with other people in the area. She used to take them to and from school until they reached high school age. They rarely had any guests. She even did the shopping herself."
Helmi said she never noticed anything out of the ordinary about the would-be bomber, and is shocked that someone from his background could allegedly commit such a crime.
Al-Sharif remembers the bomber
as being a recluse with no friends
"He was a normal young kid like all his peers. He wasn't a Sunni extremist like people we see on TV. Yes, he used to pray but just like all young men in the area who go and pray in the mosque."
Said al-Sharif, who owns a shoe repair shop in the same building, said he saw nothing in Hasan Bashandi’s behaviour to indicate he harboured any violent tendencies.
"He was a normal kid, very polite but secluded. He didn’t mingle much with people, but all in all I would describe him as a typical young man. There was nothing that stood out in his behaviour," he said.
"We occasionally used to see him go pray in the mosque and come back. But this was just like all other young men in the street who gather in Friday prayers."
Neighbours and friends who knew the Bashandi family well are refusing to believe that someone they saw grow up over the years could be behind the deadly bombing.
"We still don't believe what happened. He is very well- mannered. Neither he nor any of his family smoke even," Helmi explained.
"I think he was there by coincidence and [the explosion] happened"
She said the family celebrated life and pointed to one of the Bashandi brothers' wedding.
"[They] had music and even dancing. They even got a DJ to spin the turntable and deliver popular Arabic songs."
Al-Sharif vehemently denies Bashandi could have been involved in the bombing.
"I think he was there by coincidence and [the explosion] happened. For him to do such a thing is far from true. Just now I heard on TV that police found drugs and nails in his apartment," he said.
But the Egyptian Interior Ministry paints quite a different picture, describing Bashandi as a man with almost no friends, who spent a lot of time in the mosques and was particularly affected by his father’s death in September 2004.
Investigative profilers say Bashandi spiralled deeper into his seclusion, which they theorise may have led to his final, deadly act.
Egyptian police used DNA samples
to identify the bomber's remains
Over the course of the eight months after his father’s death, they claim the 17-year-old began to change his philosophies. They allude to several CDs containing so-called "extremist" ideologies.
"Only now did we hear from the [television] broadcasts that his attitude changed after his father's death. We never felt that or noticed any changes in his attitude. We know the family as conservative and respectful. They also said on TV something we never heard before, that he recently started to tell his mother that TV is religiously prohibited," al-Sharif told Aljazeera.net.
His father had worked as a blacksmith in a metal workshop affiliated with the government-run military factories. While his remuneration was considered adequate, neighbours say his death left his family living off his retirement savings.
On the morning of 7 April, Helmi remembers Bashandi knocking at her door. He gave her the keys to their apartment for safe-keeping till his mother returned from shopping.
He told Helmi that he was heading for the engineering faculty at the Banha campus.
It was the last she saw of him.
When he did not return by late that evening, his mother called on the district police stations and checked local hospitals and morgues.
Two days later, after the family was beginning to panic, a concerned uncle called the state security department and was given information that Bashandi may have been involved in the attack in downtown Cairo.
Later that day, members of the Bashandi family, including the sister, mother and three brothers, were detained by state security. After detailed DNA analysis and comparison, Hasan Bashandi was identified as the bomber.