Twelve years after the riots which left more than 700 Muslims dead, Mr Modi is cruising to become the leader of the world's largest democracy, which will declare results from its mammoth nine-phase general election on May 18. Mrs Jafri, however, wants him prosecuted for abetting mass murder, over what was one of India's worst ever outbreaks of communal violence.
Now 75 and suffering from diabetes, she seems an unlikely opponent to Mr Modi, 63, who is being courted by world leaders. He might, however, be unwise to underestimate her. On Friday she won another round in her fight to reopen a judicial inquiry that exonerated him of any responsibility for the riots.
Last week, she and her former neighbours held a campaign meeting in the charred ruins of their abandoned homes in Ahmedabad. It was here, on February 28, 2002, that the mob attacked, following rumours that Muslims had been responsible for the deaths of 58 Hindu pilgrims in a train fire at Godra the previous day.
'They chopped his hands and arms bit by bit'
In an interview with The Daily Telegraph, Mrs Jafri told how she saw the mob trying to force her husband to sing Hindu prayers. When he resisted "they beat him with swords," she said. "They chopped his hands and arms bit by bit."
Her claim that Mr Modi should be held to account for the massacres is based on conversations with Indian police officers, who told her they had been ordered to stay at home during the rioting. "Why does an old lady still want to fight against this powerful man?" she asked. "Because I'm on the path of truth. I will fight for justice, and I will win."
Some fellow Muslims, however, question the point of pursuing the case now. They say that Mr Modi had only been in his post as minister of Gujarat for a few days when the riots broke out, and had yet to master the levers of government.
For his part, Mr Modi denies speaking on the telephone to Mr Jafri that day. While he offered his resignation as minister in the wake of the riots, he has never publicly apologised for failing to save Muslims or visited survivors, for fear opponents would make political capital of it.
But survivors say his decision to visit the scene of the Godra train fire incident and to remember only Hindu victims still rankled with them. "I lost everything, my son, my house," said Rupaben Mody, a witness to the massacre. "I don't want him to be prime minister. All I can do is appeal to the people of India to support a mother's struggle."