"He is creating hurdles in my efforts to bolster support for the Nitish Kumar's adhikar rally", Bharti said at a private hospital where her son is undergoing treatment for suspected poisoning.
On the basis of Bharti's complaint, an FIR against has been lodged against Mandal and six others.
Bharti's son took ill soon after he returned from a fair at Bhitta village in the district on Wednesday evening. Later, the MLA rushed her son to the private hospital where his condition was said to be stable.
She alleged in her petition that her husband plotted to kill their son by poisoning him. "The boy was given samosa mixed with poison" she alleged.
"We are looking into the matter," Dhamdaha sub-divisional police officer SK Prabhat said.
Mandal, against whom Bharti's divorce petition is pending in the court, has denied the charges. "I am currently busy making arrangements for Laluji's rally at Katihar and Purnia next week", he said.