The death of an inmate at the Madison County Jail in Huntsville is under investigation, Sheriff Kevin Turner announced Wednesday.

The sheriff’s office said the inmate is believed to have attempted to kill himself. The man’s name was not released in the announcement.

The sheriff’s office said the 49-year-old man was found unresponsive in his cell about 6:30 p.m. Monday. Jail officers and medical staff members began live-saving measures. HEMSI transported the inmate to Huntsville Hospital.

The inmate died at the hospital about 2 a.m. Tuesday, the sheriff’s office said.

“All indications appear that he attempted to take his own life through asphyxia by using a bedsheet,” the sheriff’s office said in the announcement. “Preliminary findings indicate the manner of suicide.”

The inmate was booked into jail on Friday after being arrested and charged with first-degree criminal mischief.