Sao had yesterday submitted his resignation to Soren after the head of 'Jharkhand Tiger' (JT) accused him of founding the ultra outfit.
The Congress MLA also sought an independent and impartial probe into the allegations.
The police are investigating the matter after the arrest of JT head Raj Kumar Gupta and four others on September 1 in Hazaribagh district.
In his statement recorded under section 164 before a judicial magistrate recently, Gupta accused Sao of founding JT to extort money, an allegation Sao denied.