New Delhi, July 30 : In a new twist in the alleged suicide case of actor Sushant Singh Rajput, the Bihar government too has filed a caveat in the Supreme Court in actress Rhea Chakraborty's petition which seeks transfer of the Patna FIR to Mumbai where police is inquiring into the case. Sources said that former Attorney General Mukul Rohatgi will represent the Bihar government defending its probe into Sushant's death. The state government would support Rajput's father in the apex court and also oppose the transfer of FIR registered in Patna against Rhea Chakraborty to Mumbai. Rajput's father has accused Rhea, reportedly Sushant's girlfriend, for allegedly abetting his son's suicide. Earlier in the day, Sushant's father K.K. Singh filed a caveat in the Supreme Court on the plea of Rhea seeking transfer of investigation in the case from Patna to Mumbai. "Let nothing be done in the above mentioned matter without prior notice to the undersigned," said the caveat by advocate Nitin Saluja on behalf of Sushant's father. The apex court also declined to entertain a plea seeking a CBI investigation into the death of the actor. Rhea moved the apex court seeking transfer of the FIR from Patna to Mumbai where police is investigating Rajput's death by suicide. On Wednesday, after Sushant's father lodged an FIR against Rhea Chakraborty in Patna, accusing her of cheating and threatening his son, who allegedly committed suicide last month, the actress on the same day moved the Supreme Court seeking transfer of the investigation to Mumbai. Speaking to IANS, Rhea's lawyer Satish Maneshinde had said his client has electronically filed a petition in the Supreme Court, seeking transfer of investigation from Patna to Mumbai where investigation in connection with the actor's death is already in progress. Maneshinde, however, refused to share the contents of the petition. Sushant and Rhea were in a relationship before the actor's death on June 14. Sushant's father has levelled various allegations against Rhea, including taking money from his son and also threatening to disclose his medical reports to the media. Sushant's family has also accused Rhea of keeping him away from his family. Sushant's first cousin and former BJP MLA from Bihar's Chhatapur, Neeraj Kumar Singh said the FIR has been filed after the family somehow overcame the shock of the untimely and sudden demise of the young actor, and after various facts came to their knowledge. /IANS