The BJP and its allies on Thursday demanded the arrest of RJD legislator Kunti Devi and her son after he allegedly assaulted a doctor at a government hospital in Gaya district.Ranjeet Yadav, son of the Rashtriya Janata Dal (RJD) legislator from Atri assembly constituency, along with his half a dozen supporters thrashed Satyender Kumar Sinha at the Neemchak Bathani primary health centre on Wednesday evening, police said.Though Kunti Devi has denied her son's involvement in the matter, the Bharatiya Janata Party and its allies Lok Janshakti Party (LJP), Rashtriya Lok Samata Party (RLSP) and Hindustani Aawam Morcha (HAM) have demanded a stern action against the legislator and her son."Kunti Devi and her son should be arrested immediately," Leader of Opposition in the state assembly Prem Kumar said.LJP leader Pasupati Kumar Paras and HAM state president Brishen Patel also demanded action against the two. Ranjeet Yadav also faces half a dozen other criminal cases, including murder of a leader of rival party.