The Oklahoma County Detention Center said one of its detainees died Saturday morning.
Jail officials said a detention officer discovered 27-year-old Andrew Avelar unresponsive in his cell just before 4 a.m.
The officer called for staff and medical personnel to perform live-saving efforts on Avelar before he was transported to a nearby hospital.
Avelar was pronounced dead just before 5 a.m.
He was booked into the jail Jan. 31.
According to the jail's initial investigation, it appeared Avelar made a suicide attempt in his cell. The State Medical Examiner's Office will make a final determination of Avelar's cause of death.