Patna, Jan 20 (IANS): After opposition parties questioned the intentions of the Bihar police in the Rupesh Kumar Singh murder case, a senior retired IPS officer has raised doubts over the investigation and demanded a CBI inquiry into the case, monitored by the Supreme Court.

Amitabh Kumar Das, 1994 batch IPS officer (Retd) alleged that if the Bihar police carried out a fair investigation, many top politicians and bureaucrats will face imprisonment.

"I was contacted by many senior police officers and they said that there is enormous political pressure on them regarding this case. The Rupesh Singh murder is related to tenders of various departments under the state government. If its truth comes out, many ministers and IAS officials may go to jail," Das alleged in a letter to DGP Bihar.

Earlier, opposition leaders such as Tejashwi Yadav, Rajesh Ranjan alias Pappu Yadav and Madan Mohan Jha had raised doubts over the investigation.

DGP SK Singhal had indicated that a dispute over airport parking could be the reason behind the murder.

Following Singhal's statement, Tejashwi tweeted that the Bihar Police are looking for a scapegoat to save the actual culprits.

"The state home minister [Nitish] has floated a tender to find excuses to save people sitting on the top posts in his government," Tejashwi tweeted.

Rajesh Ranjan alias Pappu Yadav said that the game is on the save the actual culprits of the Rupesh Singh murder.

"Do not sell your conscience DGP Saheb. Everything is achievable but not peace. You too have kids," Yadav tweeted.

Madan Mohan Jha said that deceased's family has zero expectations from Bihar police.