The boy, also named Malcolm, has been in juvenile detention since 1 June. On that day, Dr Shabazz was found in her apartment in Yonkers, a northern suburb of New York, with the gruesome burns - third degree over 80 per cent of her body - that finally brought death last Monday. Police say Malcolm has admitted setting the fire that engulfed his grandmother.
All of last week, while New York sweltered in the upper nineties, the anguish that settled over the city was palpable. For two days, a slow snake of thousands, almost all black, formed outside the funeral home on 126th Street where Dr Shabazz lay awaiting burial. It was the same parlour that 32 years ago washed and shrouded the bullet-ridden corpse of Malcolm X.
That there should be such emotion is not hard to fathom. The black community has lost a special bridge to the charismatic orator and civil rights leader. It also lost a woman who was herself an icon of black history.
But look for any expressions of hatred against the 12-year-old Malcolm, any demands for revenge against him for what he has apparently perpetrated, and probably you will do so in vain. For reasons more complicated than they first appear, most of those mourning Dr Shabazz mourn also for him.
Thus, when prosecutors suggested following her death that they were considering upgrading the charges to murder, there were cries of dismay even if, as a juvenile, Malcolm could not be imprisoned beyond his 18th birthday. Former mayor of New York, David Dinkins declared: "He is a bright child... what we are all interested in is that he gets appropriate care and attention."
Percy Sutton, longtime Shabazz family friend and lawyer, was more blunt. "What is there that drives a prosecutor to take the last measure of pain from a family?" he asked. "What did Malcolm X do? Is it a payback? What did Betty Shabazz do to cause this pursuit? I don't understand it."
Partly, it is a matter of simple sympathy. Even before this month, the Shabazz family was afflicted by almost imponderable tragedy. On the February night in 1965 when Malcolm X was shot dead in the Audubon Ballroom in Harlem, among those present was Betty herself, then pregnant with twins. Also in the hall was their four-year-old daughter, Qubilah, who is the mother of the young Malcolm.
Qubilah has since led an unsettled life that seemed to implode in 1995 when she was charged with attempting to arrange the assassination of Louis Farrakhan, the leader of the Nation of Islam. The Shabazz family had long believed that Farrakhan had been behind the killing of Malcolm X.
Eventually there was a sentence of probation for Qubilah that was suspended in May this year. Earlier this year, however, Qubilah apparently despaired of bringing up her son in Texas, where she lives, and sent him to stay with his grandmother. Friends say the boy set the fire as a protest at the separation.
In their restraint about the boy's crime, many blacks also, however, have more than half an eye on non-black reactions. The fear is straightforward: that the killing will simply feed the white stereotype of young black males having no regard for either property or human life.
"Many of us know that he did wrong and know that he must be made to stand up and accept responsibility for that and that he must be helped," said Roberta Evans, a Manhattan nurse. "But we don't want him dragged over the coals by the other groups. This is what the black community is afraid of and the black community is very protective".