Pappu (35), arrested with illicit Haryana-made liquor, hanged himself from the window of the lock up in Banna Devi police station area last night, police said.
On the complaint of the deceased's wife, a case has been registered against constables Girish Chandra, Amarpal and Ashok Kumar and all the three have been suspended, they said.
A request for a judicial inquiry in connection with the custodial death has also been made to the chief judicial magistrate, they added.
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