The 25-year-old inmate, identified as Sombir, went to take bath but did not return, police said adding that it later found his body hanging in the bathroom.
Sombir, a resident of Barchhappar village in the district, was put behind the bars in a murder case. He was facing charges of murdering his brother's wife following some domestic dispute in May this year, Jail Superintendent Surender Singh Godara said.
Baljit, an uncle of deceased, has demanded fair investigation into his death, police said adding that the body has been sent for post-mortem.