The GRP officials said the constable identified as Lakhi Kant Pramanik (30) was posted at the residence of deputy superintendent of police (DSP) Binod Kumar Mahto.
This morning he allegedly hanged himself from a tree behind the police barrack, the officials said.
Superintendent of Railway police (SRP) HP Janardanan, who immediately reached the spot after getting the information told media persons that prima facie the incident looked like suicide.
However details would emerge only after post-mortem, the SP said adding that the body has been sent to Patliputra Medical College Hospital for autopsy.