An inmate died Sunday while in custody at the Sacramento County Main Jail, according to the Sacramento County Sheriff’s Office.

A 45-year-old man, facing a felony burglary charge, was booked on Thursday and was in a cell used by inmate to detox from narcotics, a news release said.

Sheriff’s deputies came across the man, the sole occupant in the cell, and saw he was unresponsive. They began to render medical aid and called the Sacramento Fire Department, the release said.

Firefighters were told of the incident at 10 p.m. The inmate was declared dead about 10:30, the release said.

The Sacramento County Coroner’s Office will release the man’s identity and cause of death. The Sheriff’s Office will also investigate his death.