Nitish Kumar Kumar has claimed that the special package is nothing but repackaged schemes.
Letters are flying between Patna and New Delhi over Prime Minister Narendra Modi's 1.25 lakh crore package for Bihar -- announced last month ahead of the coming assembly elections in the state.
On Thursday, a fourth missive was dispatched - from Chief Minister Nitish Kumar to Union finance minister Arun Jaitley, contending that 87% of it is repackaged schemes.
An economic package for the underdeveloped state has always been a key issue, but the political battle had started as soon as PM Modi had announced it. Mr Kumar had claimed that the Prime Minister was selling a "well-conceived myth" to Bihar.
In his Thursday's letter, Mr Kumar pointed out that some of the ambitious projects mentioned in the package need land, but the onus for that has been left to the state government, which made it non-feasible.
"You are reasonable in assuming that state will provide land or all projects you have proposed but failed to appreciate the fine point regarding additional financial burden on a poor state like Bihar," the letter read.
The 5-page letter also raised the demand for special category status, saying it was "imperative" to address the "social, economic and infrastructural backwardness of Bihar".
The exchange was started by Mr Jaitley's letter of on August 28 - which gave the details of the financial package for Bihar.
On September 4, Mr Kumar responded. "It is clear that this package for Bihar announced just before elections is nothing but a well-conceived packaged myth devised to influence people," the letter read.
Mr Jaitley wrote back, saying, the financial package was "an expression of unwavering commitment of the Union government towards overall development of the state and betterment of its people".