Under the shade of a banyan tree, a group of worshipers recite Sanskrit mantras. A couple men step forward and light a fire. Then they start walking, hands folded, as if in a trance, toward a statue.

Some drape flowers over it. Others sing songs of valor to the statue. It is of Nathuram Vinayak Godse, who assassinated Mohandas K. Gandhi, the revered father of Indian independence and a symbol of nonviolent resistance the world over.

Indians consider Gandhi one of the fathers of their nation. But the rise of a Hindu nationalist government, led by Prime Minister Narendra Modi, has uncorked many extremist beliefs, and admiration for Gandhi’s killer, among some, has become more open. It is a sign of how much India has changed in the five and a half years since Mr. Modi took power.

“Gandhi was a traitor,” said Pooja Shakun Pandey, who blames Gandhi for partition and who participated in a recent ceremony worshiping Mr. Godse on the anniversary of Gandhi’s assassination. “He deserved to be shot in the head.”

Prominent Hindu nationalists still invoke Gandhi, but in many cases they are trying to co-opt his legacy — presenting their policies, however divisive, as congruent with his beliefs. One example: a recent citizenship law pushed by Mr. Modi’s government that, critics say, discriminates against Muslims and threatens the secular state that Gandhi had envisioned.