A former government minister and 12 supporters were arrested Tuesday for allegedly killing a police officer in an attack on a police station in Uttar Pradesh, police said. Jamuna Prasad Nishad was arrested a day after he resigned as minister in Uttar Pradesh state after police said they were investigating him and his supporters for murder and arson, said Vikram Singh, a top state police official. Nishad and his backers were reportedly angry that an investigation into an alleged rape was being investigated as a case of molestation, a lesser charge. Singh said they stormed a police station on Saturday in Maharajganj, a town 300 kilometers southeast of Lucknow, killing one constable. Uttar Pradesh is notorious for politicians suspected of criminal ties. Nishad's arrest and resignation are seen as part of the ruling party's attempt to clean up the state's tarnished image as an untamed area unfriendly to business and the rule of law. Indian law bars a person from running for office once indicted by a court, which often happens years, after an arrest. Nishad has remained a state lawmaker. Police arrested Nishad's supporters on Monday in Maharajganj, Singh said. If convicted, Nishad, who already faces eight unrelated criminal investigations, could face life in prison. He is one of several state lawmakers facing criminal charges, including murder and kidnapping. Nishad did not comment immediately. Last year, another former Uttar Pradesh minister, Amarmani Tripathi, and his wife were sentenced to life in prison for the 2003 murder of the minister's pregnant mistress. Another former national lawmaker, Anand Mohan, was sentenced to death for his role in the 1994 murder of a government official. It was the first time a member of parliament received the death penalty in India.