Mr. Modi campaigning last week in Gujarat State. He was chief minister during a deadly episode of Hindu-Muslim violence in 2002.

AHMEDABAD, India — Narendra Modi, India’s most incendiary politician, is trying to cast himself as the vanguard of India’s modern industrial future. The ghosts of this city’s savage past, though, are refusing to leave his side.

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Ruth Fremson/The New York Times

A young supporter of the opposition Bharatiya Janata Party wore a mask with the likeness of Narendra Modi, the chief minister of Gujarat State.

Mr. Modi, 59, is the thrice-elected chief minister of the western state of Gujarat. On his watch, this city witnessed one of the worst episodes of Hindu-Muslim violence in the history of independent India: in the spring of 2002, mostly over three days, 1,180 people were killed across the state. Most were Muslims. Mr. Modi’s administration was accused of doing little to stop the fury and on occasion, abetting it.

On Monday, India’s Supreme Court, in its strongest move yet, ordered a special police team to investigate Mr. Modi’s role in the alleged conspiracy to attack Muslims.

With national elections under way, Mr. Modi is the biggest crowd-puller for India’s main opposition party, the Bharatiya Janata Party. And while party hierarchy means he is not the B.J.P.’s candidate for prime minister this year, he is positioning himself for the top slot in the next race.

On the campaign trail, he is sardonic, often churlish, always theatrical. At one rally, he compared the ruling Indian National Congress, the nation’s oldest party, to an aging woman. At another, he assailed the incumbent prime minister, Manmohan Singh of Congress, as so “weak” that he ought to get a medical check-up; Mr. Singh had recently recovered from heart bypass surgery.

At a third, stabbing the air with his finger, he taunted Mr. Singh for turning to the United States for support in the aftermath of the Mumbai terrorist attacks in November, which India said were the work of a Pakistan-based militant group.

“O-baaaa-maaa,” he whined, referring to President Obama. “O-baaa-maaa. Our neighbor has come and attacked us. Do something!” The crowd lapped it up, hollering, clapping and imitating his cry of “O-baaa-maa.”

Mr. Modi’s success offers a window into the B.J.P.’s delicate balancing act: It has to hold on to its radical Hindu support base even as it pitches itself as a force of prosperity and security. His rise also suggests a turning point in Indian politics, in which voters weigh what matters more: identity issues, like faith and caste, or practical issues, like electricity, water and roads. Opinion polls show that Hindutva, or Hinduness, has diminishing appeal.

With a national profile clearly in mind, Mr. Modi has assiduously sought to reinvent himself from a scruffy mascot of Hindu nationalism to a decisive corporate-style administrator. His talking points these days are Gujarat’s double-digit economic growth, private seaports and round-the-clock electricity in Ahmedabad, a booming western city that Gandhi once called home. He wears business suits to business meetings, instead of homespun tunics. He still lampoons the urban, English-speaking elite, but he is also honing his English skills.

His biggest coup has involved the Tata Nano, the world’s least expensive car. Last fall, Mr. Modi persuaded Tata Motors to relocate its Nano factory to government-owned land not far from here. The company had been buffeted by protests over land acquisition in another state.

Soon afterward, several of India’s most prominent industrialists gathered in Gujarat for a meeting and declared Mr. Modi, a former tea shop manager, fit to be a future prime minister.

Swapan Dasgupta, a columnist who advises the B.J.P. on strategy, described him as India’s “aggressive modernizer.”

The B.J.P “promises growth, good governance, development and security.” But it also returns to the party’s original ideological pillars, from pledging to build a Hindu temple on the site of a razed 16th-century mosque to resurrecting a preventive detention law that Muslims said had been unfairly applied to them.

Rarely does Mr. Modi make overt appeals to faith. He does not have to.

“Modi has learned that you have to do development to get re-elected, you have to have a secular image if you want to be prime minister,” said Ajay Umat, editor of a Gujarati-language daily newspaper, Divya Bhaskar, who has known Mr. Modi for more than 20 years.

Mr. Modi has also learned, Mr. Umat said, that his core Hindu supporters will not easily forget his original incarnation as their “protector.”

That image was sealed in 2002, after a train ferrying Hindus was set on fire by Muslims in a town called Godhra, killing 59 people on board and prompting Hindu mob attacks onMuslims across the state. The mobs stabbed, raped and set their victims on fire; they burned homes and businesses. Mr. Modi has never apologized for what happened. (His office did not respond to numerous requests for an interview with The New York Times.)

His admirers say he has moved on. They credit him for removing red tape for business, improving the state’s road networks, and cracking down on lawlessness and petty corruption. His detractors call him an autocrat. (Sonia Gandhi, the president of Congress, once called him “a merchant of death.”)

If and when Mr. Modi becomes the standard-bearer for his party, Indian voters will have to decide whether they can overlook what is called the “2002 stigma” in favor of the “aggressive modernizer.” His critics hope they will not.

“This man can’t represent India, either as a civilization or as a nation,” said Shiv Visvanathan, a sociology professor and one of Mr. Modi’s critics. “He can represent a part. He can never represent the whole. That is the sanity of Indian democracy.”

Unfortunately for Mr. Modi, the past has been hard to cast off. A police team appointed by the Supreme Court has begun to pry open several cases from 2002, making fresh arrests.

Maya Kodnani, Mr. Modi’s former minister for women and child development, was arrested on charges of helping a Hindu mob attack two nearby Muslim enclaves. She is awaiting trial on accusations of arming the mob with kerosene cans, which were then used to set people on fire. All told, the mob killed 106 people on a single day, including seven members of Abdul Majid Mohammed Usman Sheikh’s family.

Mr. Sheikh, 56, who came to the courthouse on the morning of the arrest in late March, called it the beginning of justice for the dead. Among them were his pregnant wife, three sons and three daughters. He carried their pictures in a plastic shopping bag. He said he felt “a little satisfied.”