Senior BJP leader Sushil Kumar Modi today said Bihar Chief Minister Nitish Kumar should undergo an 'agnipariksha' (trial by fire) by acting against his deputy, Tejashwi Prasad Yadav, for his alleged involvement in a corruption case. Kumar, who had earlier accepted the resignation letters of four of his ministers for their "involvement" in corruption cases, should now take the same step against his deputy, he told reporters here. "This is the chief minister's agnipariksha," added Modi. The CBI yesterday conducted raids in four cities in connection with a corruption case, in which RJD chief Lalu Prasad, his wife Rabri Devi and son Tejashwi are among the accused. "Nitish Kumar had once said he would not allow a tainted minister in his cabinet and accepted the resignations of Jitan Ram Manjhi, Awadhesh Kushwaha, Ramanand Singh and Ramadhar Singh for their alleged involvement in criminal cases," said the BJP leader. He claimed that the central probe agency lodging an FIR in a corruption case against the deputy chief minister and conducting raids at his residence reflected a "negative image" of Bihar and added that Kumar should now act against Tejashwi. "I am waiting for the chief minister's action in this case as he and his party have maintained a silence over the issue for three months now. This is the same chief minister who has constantly been asserting his government's zero tolerance policy towards corruption," said Modi. Within hours of taking oath as chief minister in November 2005, Kumar had made Manjhi resign due to an old vigilance case pending against him, the BJP leader added. Also watch: Ramanand Singh put in his papers in 2008 because of another vigilance case, Ramadhar Singh quit in 2011 due to a case pending against him over the Ram Janmabhoomi issue, whereas Kushwaha resigned after he was purportedly seen taking money in a sting operation during the 2015 Bihar Assembly polls, he said. The case against Lalu, Rabri and Tejashwi is related to alleged manipulation in awarding a contract for the maintenance of two hotels run by the IRCTC when the RJD chief was the railway minister in the then UPA government. Modi, the Leader of Opposition in the Legislative Council, asked Prasad to come up with a reply to the charges against him and his family members, instead of repeating the "oft-quoted one-liner - political vendetta". To a question, he said, "I do not need any security. I am at god's mercy."