Rights groups and survivors accuse the state government, controlled by the Hindu right-wing Bharatiya Janata Party, of not doing enough to stop the violence and even stoking it.
The religious violence was among India's worst since its independence from Britain in 1947.
"Instead of prosecuting senior state and police officials implicated in the atrocities, the Gujarat authorities have engaged in denial and obstruction of justice," Meenakshi Ganguly, South Asia director for U.S.-based Human Rights Watch, said in a statement over the weekend.
State government officials have always denied any allegations of obstruction and wrongdoing.
"All these years, there has not been the slightest hint or trace of remorse," Cedric Prakash, a Jesuit priest and rights activist in Gujarat, said Monday.
"Are these people not real? They still remember the horrors," Prakash said by telephone from Gulberg Society, a middle-class neighborhood in Ahmedabad, Gujarat's main city. At least 69 Muslims were killed there when a mob set homes on fire during the rioting.
Inside Gulberg Society's still-damaged homes, activists have hung photographs of those killed in the violence and those who are still missing.
Human Rights Watch said that while investigations of the train attack proceeded rapidly, investigations into the anti-Muslim riots that followed were "deliberately slowed down or simply not pursued."
The rights group accused Gujarat's top elected official, Narendra Modi, a senior Bharatiya Janata Party leader, of failing to conduct serious investigations and obstructing justice.
It was only after India's top court appointed a special investigation team in 2009 that two top leaders, Maya Kodnani, a minister in the state Cabinet, and Jaideep Patel, a leader of the hard-line Vishwa Hindu Parishad, or World Hindu Council, were arrested on charges of leading mobs that attacked Muslims during the riots. Both are still on trial.