Police arrested a shopkeeper for axing to death a couple from a lower caste for not promptly paying a meager debt of 15 rupees (22 cents) for groceries, an official said on Friday. District Magistrate Pramod Chandra Gupta said the upper caste shopkeeper killed the couple in a rage Thursday, severing both their heads, when they asked for more time to pay for the groceries they bought from his shop in Mainpuri, a town in Uttar Pradesh state. The Dalit couple were construction workers and left behind five children, Gupta said. "The shopkeeper panicked after killing the couple and hid in the village. But he was arrested," he said. The shopkeeper is from the Brahmin caste. Formal charges in the killings would be filed after the police investigation is completed. Mainpuri is 300 km southwest of Lucknow, the capital of Uttar Pradesh state. Attacks against Muslims and Dalits have risen since Prime Minister Narendra Modi's Hindu-nationalist party came to power two years ago. Four low-caste Dalit community men were beaten by Hindu hardliners while trying to skin a dead cow in western India earlier this week. Hindus consider cows to be sacred, and the slaughter of cows is banned in many parts of India. Slaughtering a cow carries a punishment of up to seven years in jail. The Dalit protests have turned violent in some towns. In western Gujarat state's Amreli district, a police constable was killed when angry mobs pelted police with stones. Although caste discrimination was banned soon after India's independence from Britain in 1947, the practice persists. Successive governments have set quotas for jobs and university spots to level out disadvantages faced by lower castes, but it has been difficult to change social attitudes.