Zamir, Shamshad, Ali Hasan and Zakir were arrested for allegedly attacking Anju on October 21 when she was cutting trees from a jungle, police said.
Tension had gripped the village when Dalits blocked the Delhi-Dehra Dun national highway protesting the alleged murder of the woman, who succumbed to burn injuries on October 22.
Case of attempt to murder and Prevention of Atrocities Act (POA) had been registered against the four accused after the blockade.
However, according to police, Anju's house caught fire in which she sustained burn injuries and succumbed in hospital.
