"Rafale deal details cannot be disclosed to the country? Why? Because it smacks of nepotism and kickbacks? Why was MRCA scrapped? Because new deal allows for secrecy, hence corruption? BJP parking huge funds for elections with such deals?," the RJD supremo said on his twitter handle.
Mr Prasad has been behind the bars in Ranchi since December 23, when he was convicted by a special CBI court in connection with fraudulent withdrawal of money from the Deoghar treasury.
He was subsequently awarded three years and six months' imprisonment in the case followed by conviction and five years' imprisonment in another case relating to illegal withdrawal from Chaibasa treasury.
Accusing the BJP-led NDA of having "framed" him in the cases, the RJD supremo has persisted in his attacks on the PM Modi government, while speaking to journalists outside courts and also on the social media.
In another tweet, Mr Prasad alleged "Indian Air Force's need for huge numbers was ignored because opportunity for corruption and huge kickbacks was being eyed....It is BJP's election preparedness deal. Not IAF and the country's deal".
Mr Prasad, a long-time ally of the Congress, has been a strong votary of opposition unity against BJP.