"He is in judicial custody, it is for the jail authorities to answer. The police have nothing to do to it," Commissioner of Police, Anant Kumar told PTI over telephone from Siliguri.
CPI(M) leader Ashok Bhattacharya went to visit Sahani during the day and found him chained to the bed.
Live footage of the SFI student leader being chained to the bed was shown on television.
"The West Bengal government is claiming that it is a government with a human face. But the condition of human rights in Bengal is worse than the days of emergency," Left Front Chairman Biman Bose said.