Nitish Kumar's government has moved the Supreme Court over Shahabuddin's bail.
Gangster-turned-politician Mohammad Shahabuddin's release from jail has been challenged in the Supreme Court by the Bihar government, in which his party RJD is a partner.
Mr Shahabuddin, a former lawmaker of Lalu Yadav's RJD or Rashtriya Janata Dal, walked out of jail last weekend after 11 years. He faces 40 criminal cases including murder, kidnapping and extortion.
The 49-year-old was jailed in 2005 when Nitish Kumar first came to power, ending the RJD and Lalu Yadav's 15-year rule.
Mr Kumar was credited with halting Mr Shahabuddin's reign of terror by doggedly pursuing cases against him.
After his release last week on bail, the opposition BJP accused Mr Kumar of giving in to coalition politics and facilitating the return of "jungle raj" in Bihar.
But Mr Kumar's Janata Dal United made it clear that there was no question of "any compromise" in cases against Mr Shahabuddin,
On Thursday, the Chief Minister had said: "All I can say is that the law will take its course in Bihar".
Mr Shahabuddin has made it clear that he continues to bear a grudge against the chief minister despite his party's new equation with Mr Kumar. Moments after walking out of jail, he called Mr Kumar a "chief minister of circumstances", which appeared to telegraph the resentment in Lalu Yadav's party at being led by Mr Kumar despite winning more seats in the November assembly elections.
Amid reports that the strongman has shaken up the delicate ruling alliance, Lalu Yadav on Thursday denied any rift with Nitish Kumar and said Shahabuddin's bail was a court decision, not a political move.
Mr Shahabuddin's bail was also challenged today by a businessman whose three sons were allegedly murdered by the politician. Senior lawyer Prashant Bhushan moved court on behalf of Chandrakeshwar Prasad, whose sons were kidnapped and murdered in 2004. The petition will be heard on Monday.
"I'm not bothered at all. Those who get bothered, people try to bother only them," Mr Shahabuddin said in response to the petitions against him.